What are the issues related to medical treatment that prolongs life of questionable quality?

Here are some quotes from commentaries on the monastic rules.

The Bhikkhus' Rules --
A Guide for Laypeople

  Properly considering medicinal requisites for curing the sick, I use them: simply to ward off any pains of illness that have arisen, and for the maximum freedom from disease.

Also, "praising the advantages of dying" is considered in the same category as "intentionally causing death":

  Should any bhikkhu intentionally deprive a human being of life, or search for an
  assassin for him, or praise the advantages of death, or incite him to die (saying): “My
  good man, what use is this evil, miserable life to you? Death would be better for you than
  life,” or with such an idea in mind, such a purpose in mind, should in various ways
  praise the advantages of death or incite him to die, he also is defeated and no longer in
  affiliation.

The Khandhaka Rules

  “A sick person endowed with five qualities is hard to tend to: He does what is
  not amenable to his cure; he does not know the proper amount in things
  amenable to his cure; he does not take his medicine; he does not tell his
  symptoms, as they actually are present, to the nurse desiring his welfare ...

I think the above implies that the patient has some kind of duty of care towards their nurse (as well as vice versa).

The Patimokkha Rules

  The Commentary extrapolates from this case to apply the dukka˛a to all
  attempts at suicide, including even the decision not to take food when motivated
  by a desire to die. However, it then runs into the question of how far this penalty
  applies to a bhikkhu who is ill. Its verdict: As long as medicine and attendants are
  available to him, the penalty would still apply. But then it lists two cases where
  the penalty would not apply: (a) A bhikkhu is suffering from a long and serious
  illness, and the attendant bhikkhus are fed up with caring for him, thinking,
  “When will we be free of this sick one?” If the bhikkhu reflects that, even with
  medical care, his body won’t last and that the bhikkhus are being put to
  difficulties, he incurs no penalty in refusing food and medicine. (b) A bhikkhu—
  reflecting that his illness is harsh, the forces of life are running out, and yet the
  noble attainments appear to be within his reach—may refuse food and medicine
  without penalty.

  The Commentary’s deliberations here show how difficult it is to legislate in
  this area, and there are reasons to question the way it applies the Great
  Standards here. Case (b) is apparently derived from SN 4.23, where Ven.
  Godhika takes his life and gains arahantship just moments before death; and
  from SN 35.87, where the Buddha says that one who puts down this body
  without taking up another body dies blamelessly. However, in arriving at its
  verdict in this case, the Commentary has to add the factors of motivation and
  perception to the equation, factors that are absent from the rule on which the
  judgment is based. It also leaves unanswered the question of how harsh the
  86
  disease has to be, and how near the anticipated attainments, to qualify for this
  exemption.

  This same holds true for case (a), which entails even more dubious reasoning.
  The Commentary’s judgment here has no clear precedent in the Canon; there is
  no clear line for deciding exactly how bad the illness and how fed up the
  attendants have to be for this case to apply; and why should the feelings of other
  people determine when it is or is not allowable to refuse food?

  It is worth noting that the origin story to the original rule here gave the
  Buddha the opportunity, had he wanted it, to formulate a general rule against
  attempted suicides, but he chose not to. He later formulated this subsidiary rule
  only when a bhikkhu attempted a suicide in a way that endangered the life and
  safety of another person. Thus a more appropriate way of applying the Great
  Standards to this subsidiary rule would be to extend it only to cases of that sort:
  where a bhikkhu’s attempts at suicide would bring danger to another person’s
  life and limb.

  As for ways of attempting suicide that do not endanger others, it seems
  better to follow the Buddha’s wisdom in not legislating about this issue at all, and
  to treat it as a matter of Dhamma rather than Vinaya. In other words, one
  should keep in mind his comment in SN 35.87 that the only blameless death is an
  arahant’s. If, lacking that attainment, one chooses to refuse food when ill to
  speed up one’s death, one should be heedful of the risks that death and rebirth
  can involve.


How to exercise goodwill in social circle?

Danilo,
If one understands goodwill or meritious deeds as something to nurish on, to "experiance", to gain pleasure out of it, at first place, one has failed the deeds so that they bring benefit. Practicing means to watch over causes (e.g. ones actions, state of mind) and not grasping ofter effects at fist place: "Because I like to have this, I do that..."
How ever, what ever you can contibute is aside of outwardly things for others benefit, if able to fill a lack, virtue (abstain to harm) and thoughts of goodwill. What ever they might be able and willing to take or give, that's their case. No one can help others so also others if they feel fine and have thoughts of metta torward you, might not be able to really help you out of missery. Ever thought that all around you have actually thoughts of metta torward to you?
Why would you or do you like to put nurishment into a unbenifical relation (e.g. lower than you?), if not simply for your own desire or expected rewards from it (in the sphere of sensuallity and identification), hmm?
Are you really that willing to associated with admirable people? Or do you actually seek simply after relations and like to nurish on Dhamma together? Well, there are plenty of such "feeding away the Gems social groups" and they are really hardly bound to each other :-)
So like always, the arrow can be found in the own heart and it's of cause not easy to come accross one who might point out and directly touch the suppurative focus. That's why they usually put a lot of effort into defend against those who are above them.
Do you fight them as well or do you seek after those who seem to have not a little metta for you?
Metta, if really right practiced gives realease, releases from feelings of being in dept, and does not bind or nurish for unskillfulness.
At least, hold on of what has real value:

"Bhikkhus, I do not know anything else that arouses non arisen merit [1] and fades arisen demerit[2] as good companionship. Good companions arouse non arisen merit and fades arisen demerit. This is the first.

"Bhikkhus, I do not know anything else that arouses non arisen demerit and fades arisen merit as evil companionship. Evil companions arouse non-arisen demerit and fades arisen merit. This is the second.

"Bhikkhus, the misery from the decrease of relations is nothing in comparison to the decrease of wisdom. Bhikkhus, of decreases the decrease in wisdom is miserable. This is the sixth.

"Bhikkhus, the increase of relations is nothing in comparison to increase of wisdom. Therefore you should train, we will increase in wisdom. This is the seventh.

"Bhikkhus, the misery from the decrease of wealth is nothing in comparison to the decrease of wisdom. Bhikkhus, of decreases the decrease in wisdom is miserable. This is the eighth.

"Bhikkhus, the increase of wealth is nothing in comparison to increase of wisdom. Therefore you should train, we will increase in wisdom. This is the ninth.

"Bhikkhus, the misery from the decrease of fame is nothing in comparison to the decrease of wisdom. Bhikkhus, of decreases the decrease in wisdom is miserable. This is the tenth."

Kalyāṇamittādivaggo: Good companionship and others

If wishing to grow, you have to seek for ways to step out of your usual relations and bound that you are able to find more sublim. If you just nurish around with likeminded wasters of merits, just go out for some hunts from the more sublime to go them back to nurish it of, like not proper social communities are usual working, then, what is it's benefit?
The more sublime are no more avaliable, sind having not put nurishment into a relation, your current community, relation with it, it's just a matter of time, that it will break apart and nothing has been gained aside a big belly or a hydrocephalus from filling up with unwise thought.
You asked:

Or am I thinking too much and should only intend to keep a heart of goodwill rather than make a active effort to preserve or increase their wellbeing?

What do you think?
If you find a group delighted to visit the monks (e.g. those not sitting on such tables), if you find relation and ways to nurish it, if you invest into the more sublime rather to nurish on the inferior, that would be of benefit for you and properply the best you could do for those you "leave behind", with a heart of goodwill, compassion, joy and equanimity, approaching the some times, "Come, lets visit the monks and do something for our longtime benefit."
If comming, good. If not: even more release or?

"Jivaka, when a lay follower himself is consummate in conviction and encourages others in the consummation of conviction; when he himself is consummate in virtue and encourages others in the consummation of virtue; when he himself is consummate in generosity and encourages others in the consummation of generosity; when he himself desires to see the monks and encourages others to see the monks; when he himself wants to hear the true Dhamma and encourages others to hear the true Dhamma; when he himself habitually remembers the Dhamma he has heard and encourages others to remember the Dhamma they have heard; when he himself explores the meaning of the Dhamma he has heard and encourages others to explore the meaning of the Dhamma they have heard; when he himself, knowing both the Dhamma & its meaning, practices the Dhamma in line with the Dhamma and encourages others to practice the Dhamma in line with the Dhamma: then to that extent he is a lay follower who practices both for his own benefit and for the benefit of others." On Being a Lay Follower

Fullfil the duties you have as a recipient, fullfil you duties toward the releations of your desires. And if the fulfillment of the duties goes agains of what is good, praisworthy and requires harm, quite to further nurish the relation In that way you arrive at good relations if avaliable to you or to minimum do not nurish unhealty bound for times later, when circumstances might be better. At least don't forget that you could be the only one able to escape the circle of death and suffering amoung your tripes and what would be the benefit for all if you don't take on a seldom change for you and all others? Beings are food and nurish on food. So there is nothing that is wiser as to use useful food to seek after freedom of desire for food. If that is reached one may return but it's seldom that you might be that welcome if you can be no more regarded as giver of food they desire.
Thats is why you would never find wise or people having chanced their ancestor-ship sitting together on a table with common people and even the proper occasions for eating together with ones kind, are less and not for the sake to increase boundage.
[Note: This is a gift of Dhamma, not meant for commercial use or other lower wordily gains by ways of exchange or trade.]


Within Theravāda tradition, what are the differences in doctrine and practice between schools and sects around the world?

It appears that some teachers and traditions are more focused on samatha and jhana like Pa Auk Sayadaw and Ajahn Brahm.

And then there are other teachers and traditions that are more focused on vipassana like Mahasi Sayadaw, Ledi Sayadaw, Sayagyi U Ba Khin and his student S.N. Goenka, Ajahn Tong Sirimangalo and his student Yuttadhammo.

Samatha is cultivation of concentration and vipassana is cultivation of insight.

Ultimately both are needed.


Mindfulness of Breathing, Mindfulness with Breathing

Mindfulness ('sati') means 'to remember'. The breathing as a meditation object cannot be 'remembered'. Instead the breathing is observed, which is called 'anupassi'.

The purpose of 'mindfulness' in Buddhism is 'to remember' to keep the mind in a state of right view & right intention (refer to MN 117) or 'to remember' to keep the mind free from covetousness & distress (refer to MN 118; MN 10; etc).

Therefore, to practise 'mindfulness of breathing' is an impossibility because mindfulness (sati) means to remember rather than to observe (anupassi).

Instead, the practise is 'mindfulness with breathing', which means to remember to keep the mind free in right view free from craving, as instructed in the four noble truths. When this is properly done, awareness/observation of breathing will naturally arise due to the quiet & silence of the mind.

Thus, mindfulness with breathing is remembering to keep the mind free from craving with awareness of breathing arising automatically/non-volitionally as the 'sign' of this right mindfulness.

Those that try to practice mindfulness of breathing rarely progress because the mind must let go of craving to progress; which includes letting go of the craving or intention to watch the breathing.

Ideas about 'mindfulness of breathing' are yogic or Hindu meditation.

'Mindfulness with breathing' is Buddhist meditation.


What should you do when someone teaches false Dharma?

You can share with them DN 16's Four Great Referrals:

“Here, monks, a monk might speak like this: ‘I have heard this directly from the Gracious One, friends, directly I learned it: “This is the Teaching, this is the Discipline, this is the Teacher’s Dispensation.”’ That monk’s speech, monks, is not to be rejoiced over, not to be scorned at. Without having rejoiced over it, without having scorned it, after learning those words and syllables well, they should be laid alongside the Discourses, they should be compared with the Discipline.
If, when these are laid alongside the Discourses, compared with the Discipline, they do not fit in with the Discourses, they do not compare well with the Discipline, you may here come to this conclusion: ‘Certainly this is not the Gracious One’s word, it is not well learned by that monk,’ and, monks, you should abandon it. If when these are laid alongside the Discourses, compared with the Discipline, they do fit in with the Discourses, they do compare well with the Discipline, you may come to this conclusion: ‘Certainly this is the Gracious One’s word, it is well-learned by that monk.’ This, monks, is the first Great Referral you should bear in mind.

That religious group will have no ground to criticize you for the above comes straight out of the Buddha's Discourses. Also freely share good Dhamma resources like accesstoinsight.org, suttacentral.net, tipitaka.wikia.com, etc. so that group members can go and find out the truth for themselves.


Do Theravada monks search for reincarnation of teachers?

No. We do not have this practice. At lease not in my country, Myanmar. Let Karma handles reincarnation.


The Buddha smiles many times in the suttas, in fond remembrance of experiences that brought great wisdom.

MN83:2.1: Then the Buddha smiled at a certain spot.

The Buddha does not smile at the suffering of others. His smiles are never cruel. His smiles are for the remembrance of great wisdom and insight that can be shared. The Buddha smiles for us all, never against any.

MN83:21.16: Ānanda, I say to you:
MN83:21.17: ‘You all should keep up this good practice that I have founded. Do not be my final men.’”
MN83:21.18: That is what the Buddha said.
MN83:21.19: Satisfied, Venerable Ānanda was happy with what the Buddha said.
(END)


Meditation to control anxiety and hyperactivity?

I think most Buddhist traditions agree that while meditating, you should concentrate on your breathing, and note when/if your mind starts to wander.  So if you have a spasm, you don't have to deny it or feel like a failure, but you recognize that it's happening, but also maintain your focus elsewhere.  You're focusing on your meditation, and whatever happens with your body goes on in spite of that because you're human, but doesn't have to detract from your focus.  You can tell your focus where to direct itself.

I know it's popular to say meditation can help with spasms and restlessness.  I think people say that because they find it teaches them to be at peace doing nothing, and that they can choose not to worry or think negative (or any) thoughts.  Personally, I'm not at that level, and I tend to become more worried when I'm not doing anything.  Perhaps for that reason, I don't schedule very long meditation sessions.  If I say I'll meditate only for 15 minutes, then I can believe that it's okay to meditate and give the meditation my full attention for that time.  If I schedule a longer time, then I have trouble really believing that it's a good use of my time, and I get fidgety.


Is yoga an acceptable form of meditation for a practicing Buddhist?

It depends on what your definition of 'acceptable' is.  Will it benefit you?  Absolutely.  For one, a case can be made that yoga is a mindfulness-of-the-body meditation and that it can even go beyond that - incorporating other aspects of sati (mindfulness).  I think it's also safe to say that all five of the hindrances can be temporarily suppressed during intense yoga and may even give rise to access concentration (upacarasamadhi).

Still, I don't think it's a perfect substitute for the kind of meditation the Buddha taught.  For starters, I wonder whether true jhana is available to someone in an asana other than a variant of the lotus position.  You'll be able to attain some amount of samatha, but the degree will be lessened by the effort it takes to maintain the other asanas.  Outside of lotus, I also don't think you'd be very stable, physically speaking, and that you'd probably just wind up falling over!  But maybe you aren't even looking to attain jhana.  Who knows!  There is precedent that such states aren't a prerequisite to enlightenment.

As per 'sects' of Buddhism that use physical excursion, well, there is a rich tradition of doing prostrations, schools like Tendai have their mudras (but I'm guessing that's not the kind of exertion you're talking about), and many martial arts schools with a Zen slant pay strict attention to bodily position - especially Japanese styles like iaido (and come on - meditate with a sword?  How cool is that!).

So yes - beneficial, absolutely.  A true alternative?  Mmmm...probably not.


What Changes have Happened to the Pali Canon?

The Scriptures or the Doctrine of the Supreme Buddha is called the Sutta Pitaka, and consists chiefly of instructive discourses delivered by the Buddha to both the Sangha and the laity on various occasions. A few discourses, expounded by disciples such as the Venerable Sariputta, Moggallana, and Ananda, are incorporated and are accorded as much veneration as the Word of the Buddha Himself, since they were approved by Him.

The Sutta Pitaka consists of the following five Nikayas(Collections):

Digha Nikaya (Collection of Long Discourses)
Majjhima Nikaya (Collection of Middle-length
Discourses)
Samyutta Nikaya (Collection of Kindred Sayings)
Anguttara Nikaya (Collection of Gradual Sayings)
Khuddaka Nikaya (Smaller Collection)

There are no changes made to the first four, but the fifth got expanded with time. Khuddaka Nikaya, the fifth, is a minor or smaller collection. Although termed "smaller", it is in fact the largest as more and more books have been added to it over the years. It has grown to 15 books in the Thai and Sri Lankan versions. In 1956, the Sangha Council in Burma added another 3 books, which are not the Supreme Buddha's own words. These 3 additions are additions are Questions of King Milinda, Petakopadesa and Nettipakarana. This is how the Khuddaka Nikaya grew from a minor collection to become a major collection! In the future, say in 500 or 1000 years' time, this would definitely create more confusion. Out of the 18 books now, probably only 6 are reliable in that they do not contradict the earliest 4 Nikayas. These 6 reliable books are the Dhammapada, Sutta Nipata, Theragatha, Therigatha, Itivuttaka and Udana.. This is how the Khuddaka Nikaya grew from a minor collection to become a major collection! In the future, say in 500 or 1000 years' time, this would definitely create more confusion. Out of the 18 books now, probably only 6 are reliable in that they do not contradict the earliest 4 Nikayas. These 6 reliable books are the Dhammapada, Sutta Nipata, Theragatha, Therigatha, Itivuttaka and Udana.

But I personally would trust the Questions of King Milinda and Nettipakarana a whole lot more than the Abhidhamma, which got added much later on. I will not go into Abhidhamma (the third basket of the Tipitaka) as it will confuse things in my humble openion. When there are nearly 18,000 suttas that are found in the canonical texts why would one want to check the Abhidhamma? It came only after the 3rd Buddhist Council. So my advice to you is to please limit yourself to reading only canonical texts (Sutta Pitaka) until you are fully established in the Path. Do not go even into the Visuddhimagga – it is only a thesis that Buddhagosha Thera wrote to show his qualifications.


Vedana: does it include feeling sleepy, dizzy, alert…

I'm still not sure how to regard sensations that at least in Western terms are not simple sensory input

In the Pali suttas, 'vedana' refer to: (i) pleasant; (ii) unpleasant &; (iii) neither-pleasant-nor-unpleasant feelings that occur with sense impressions.

When the mind lacks mindfulness-&-wisdom, pleasant feelings give rise to the defilement/urge of greed/lust/love; unpleasant feelings give rise to the defilement/urge of hatred/anger/irritation; and neither feeling can give rise to confusion.

  but which also do not imply any attachment or revulsion

Vedana/feelings are not attachment or revulsion. For example, if you break your leg, that is an unpleasant feeling. The revulsion (hatred) or attachment is a separate matter.

  hunger, fatigue and so on.

Hunger begins with an unpleasant/painful feeling but, ordinarily, quickly gives rise craving. You should try to separate the painful feeling from the craving. Feeling/vedana is not an 'urge' & not 'thinking'. Feeling is the mere painful sensation.

Fatigue is not a vedana. It is a lack of energy, either related to exhaustion of the physical body or defilements of the mind weighing down the mind. Fatigue is classed as a 'hindrance' ('nivarana') rather than a 'vedana' ('feeling').

Thus hunger is a proper object of mindfulness, where the meditator is vigilant towards & subdues craving & excitement towards food; thus attentive only to the painful stomach sensation.

Fatigue is a difficult & subtle object of mindfulness; unless one is a very skilled meditator. Generally, if fatigue arises, the meditator should focus on their physical posture; or change posture to standing or walking; or otherwise have some rest and sleep in bed. Refer to this link about 'sloth & torpor'.

  Bhikkhus, dependent on the eye and forms, eye-consciousness arises; the meeting of the three is contact; with contact as condition there
  arises a feeling felt as pleasant or painful or
  neither-painful-nor-pleasant. When one is touched by a pleasant
  feeling, if one delights in it, welcomes it, and remains holding to
  it, then the underlying tendency to lust lies within one. When one is
  touched by a painful feeling, if one sorrows, grieves and laments,
  weeps beating one’s breast and becomes distraught, then the underlying
  tendency to aversion lies within one. When one is touched by a
  neither-painful-nor-pleasant feeling, if one does not understand as it
  actually is the origination, the disappearance, the gratification, the
  danger, and the escape in regard to that feeling, then the underlying
  tendency to ignorance lies within one. Bhikkhus, that one shall here
  and now make an end of suffering without abandoning the underlying
  tendency to lust for pleasant feeling, without abolishing the
  underlying tendency to aversion towards painful feeling, without
  extirpating the underlying tendency to ignorance in regard to
  neither-painful-nor-pleasant feeling, without abandoning ignorance and
  arousing true knowledge—this is impossible. MN 148


Not quite on the topic of Kassaka Sutta, but regarding Heart Sutra roots in Pali Canon, one line of thinking traditionally connects the prajna-paramita genesis with Shrenika the Wanderer, also known as Vacchagotta of Pali Canon. Here I will post a couple of relevant quotes:

(from Aṣṭasāhasrikā Prajñāpāramitā Sūtra)

  ...
  Also, not of body, nor feelings, nor thoughts, nor volitions,
  Nor of consciousness, position even a little do not bother him.
  Thus, to all dharmas not getting stuck, not getting caught into traps of abstractions (aniketacari)
  Not clinging, he attains awakening of the Lucky Ones.

  As venerable Shrenika the wandering beggar,
  Realization acquired, without precisely grasping the skandhas,
  Just so bodhisattva, intuits real nature of things (dharmas).
  And does not seek cessation (nirvritti) but abides in wisdom.

(from Conze's notes on Aṣṭasāhasrikā Prajñāpāramitā Sūtra)

  Shrenika Vatsagotra was a “Wanderer,” i.e. a non-Buddhist ascetic, whose conversations with the Buddha form one section of the Samyuktägama of the Sarvastivadins. On one occasion (SA 105, MN 72, SN 44.8) Shrenika raised the question of the “true self,” which he identified with the Tathagata. The Buddha told him that the Tathagata could not be found in the skandhas, outside the skandhas, or in the absence of the skandhas. In a supreme act of faith Shrenika was willing to accept the Tathagata in spite of the fact that he could not be related to any of the skandhas.

(from MN 72)

  "Does Master Gotama have any position at all?"
  "A 'position,' Vaccha, is something that a Tathagata has done away with. What a Tathagata sees is this: 'Such is form, such its origin, such its disappearance; such is feeling, such its origin, such its disappearance; such is perception… such are mental fabrications… such is consciousness, such its origin, such its disappearance.' Because of this, I say, a Tathagata — with the ending, fading out, cessation, renunciation, & relinquishment of all construings, all excogitations, all I-making & mine-making & obsession with conceit — is, through lack of clinging/sustenance, released."
  ...
  "Even so, Vaccha, any physical form [Any feeling... Any perception... Any fabrication... Any consciousness] by which one describing the Tathagata would describe him: That the Tathagata has abandoned, its root destroyed, made like a palmyra stump, deprived of the conditions of development, not destined for future arising. Freed from the classification of form [feeling, perception, fabrication, consciousness], Vaccha, the Tathagata is deep, boundless, hard to fathom, like the sea.

Some thoughts and bibliography on Shrenika can be found in THE BRAHMACĀRIN ŚREṆIKA: EARLY SŪTRA SOURCES OF THE PRAJÑĀPĀRAMITĀ work by M.B. Orsborn (釋慧峰) here (I hope the link works).

Another work connecting this topic (of skahdhas/conceit/I-making/anatta/non-abiding) with the roots of Prajna-Paramita and Shunyata in early texts, is "The Concept of Emptiness in Pali Literature" by Medawachchiye Dhammajothi Thero. You can download it here (scroll down for the Download button). Here is what it says in conclusion:

  It has been shown that "Anatta" as used in early Suttas, did not merely mean the absence of an individual soul, but meant also the absence of any entity in both compounded (Samkhata/Samskrta) elements as well as in uncompounded (Asamskhata, Asamskrta) elements, that is Nibbana. Thus, it has been clearly shown that Anatta means "emptiness" of everything, including Nibbana (Nirnvana).
  ...
  A chapter was denoted to the study of various meditational practices recommended in early Buddhism, that lead to the realization of Sunna. Special focus was laid on two suttas namely Cula-Sunnata and Maha-Sunnata, both of the Majjhimanikaya. These while showing that the Buddha emphasized internalization of the understanding of the voidness of everything describes also how this could be done. This chapter will be of interest to those who wish to understand how meditative practice could be utilized to personally experience the voidness of all phenomena.

(from Cula-Sunnata Sutta)

  "Further, Ananda, the monk — not attending to the perception of the dimension of nothingness, not attending to the perception of the dimension of neither perception nor non-perception — attends to the singleness based on the theme-less concentration of awareness.

(from SA 926, which explains Shrenika's meditation)

  He meditates not leaning on Earth, Water, Fire, Air, the place of
  Infinity of Space, the place of the Infinity of Consciousness, the
  place of Nothingness, the place of Neither-Perception-nor-non-Perception;
  he meditates not leaning on this world, the world hereafter, the sun or moon, on whatever is seen, heard, sensed, cognized, obtained, sought after, followed
  after by mind, without leaning on them he meditates, because he has un-done the notion of Earth, Water... etc. -- he meditates not leaning on anything at all (na sarvam sarvam iti nisritya dhyayati).

(from Cula-Sunnata Sutta)

  "He discerns that '[Even] This theme-less concentration of awareness is fabricated & mentally fashioned.' And he discerns that 'Whatever is fabricated & mentally fashioned is inconstant & subject to cessation.' For him — thus knowing, thus seeing — the mind is released from the effluent of sensuality, the effluent of becoming, the effluent of ignorance. With release, there is the knowledge, 'Released.' He discerns that 'Birth is ended, the holy life fulfilled, the task done. There is nothing further for this world.'

(from Maha-nidana Sutta)

  This is the extent to which there is birth, aging, death, passing away, and re-arising. This is the extent to which there are means of designation, expression, and delineation. This is the extent to which the sphere of discernment extends, the extent to which the cycle revolves for the manifesting of this world — i.e., name-and-form together with consciousness.
  ...
  Having directly known the extent of designation and the extent of the objects of designation, the extent of expression and the extent of the objects of expression, the extent of description and the extent of the objects of description, the extent of discernment and the extent of the objects of discernment, the extent to which the cycle revolves: Having directly known that, the monk is released.


What are the toughest thoughts to 'catch'?

While BonnWarapol's five higher fetters would be the most difficult to eradicate for all non-arahants, for a beginner in meditation, the hardest to eradicate would be the five hindrances (pañca nīvaraṇāni):

Sensual desire (kāmacchanda)
Ill-will (vyāpāda)
Sloth and torpor (thīna-middha)
Restlessness and remorse (uddhacca-kukkucca)
Sceptical doubt (vicikicchā)

The commentaries by Ven. Nyanaponika Thera here or by Ven. Ajahn Brahm here, would provide more information on these. This video by Ven. Yuttadhammo Bhikkhu would also be helpful.


Difference between neutral Karma and no Karma

To the best of my knowledge, there is no such thing as neutral karma. As you rightly surmise, it would be the same as non-karma. This is because karma in Buddhism refers to ethical intention, not the act itself:

  cetanāhaṃ, bhikkhave, kammaṃ vadāmi. cetayitvā kammaṃ karoti — kāyena vācāya manasā.

  It is intention, bhikkhus, that I say is karma. Having intended, one performs karma, by body, speech, or mind.

  (AN 6.63)

In Theravada Buddhism, consciousness without ethical intention is called "avyakata" or "indeterminate", and is "karmically neutral", which is not the same as being "neutral karma", a term that doesn't make much sense from a Buddhist point of view.

  avyākata

  lit. 'indeterminate' - i.e. neither determined as karmically 'wholesome' nor as 'unwholesome' - are the karmically neutral, i.e. amoral, states of consciousness and mental factors.

  They are either mere karma-results (vipāka, q.v.), as e.g. all the sense perceptions and the mental factors associated therewith, or they are karmically independent functions (kiriya-citta, q.v.), i.e. neither karmic nor karma-resultant.

  http://www.palikanon.com/english/wtb/a/avyaakata.htm


After Nibbana, can one be reborn again in Samsara?

Theravada Buddhist Perspective:

  After Nibana, can one be reborn again in Samsara?

No, that is not possible. When reaching Nibbana one has destroyed all fetters. One has uprooted all defilements. There exists no longer Ignorance (Avijja) which binds beings to Samsara. One has freed oneself from the cycle of rebirth.

  If you attain Nibanna, can you be reborn again in Samsara if you wish?

No, that is not possible. Volition/intention no longer has any potency. Actions no longer bear fruits. Actions become merely "functional" (kiriya) in nature.

  Is Nibana final?

Nibbana is final when one has reached the forth stage of Enlightenment, i.e. Arahantship. At that stage the practitioner has destroyed all ten fetters. As a result of that, further rebirth is not possible.


Distraction one of the two main obstacles in meditation (the other is dozing off or even falling asleep). Many people get distracted by sound.

It's normal and as long as you keep getting distracted you have two choices:
1) keep sitting there, and keep bringing your attention back to your meditation object
2) quit meditating.
3) change your meditation. (headphones, change in meditation object etc. see below)

There is no expected time limit within which you are supposed to stop being distracted. Distraction happens.

From the way you describe it - you don't just note the distraction and then get back to meditating. You are also getting annoyed at yourself. So note that too.

Patience. Patience. Patience. Remember that this is all part of the course & that as you are not living on a mountain somewhere, your conditions are not ideal. So be patient with yourself. I'll repeat myself again: be patient with yourself.

One alternative is that when you don't meditate with plugs (which I do think an excellent idea, btw), is to meditate on sound instead. That way the distraction has become the object. This may change the meditation dynamic.

Good luck. And remember: the fact that you are still regularly sitting there is in itself an achievement. Don't be too hard on yourself. And perhaps read something by Pema Chodron? She's very good at reminding us of being kind to ourselves.


Performing magic breaking the fourth precept(lying)?

I don't personally see any problem with it. Although what you are saying is technically untrue, in the case of stage magic the audience knows that the performer is using sleight of hand and that it's just a trick. It's no more deceptive than telling a joke or a fairy tale. Technically the words aren't true, but the listener knows that. Unless you are trying to convince people that you actually do have powers like some fraudulent faith healers do and stuff, I wouldn't worry about it.


As a Buddhist, how shall we make sense of the notion that there is no such thing as a Soul?
I'm not sure why you think that "Soul" is a helpful belief.
I think that "soul" is usually taught as being/meaning something permanent, which maybe contradicts the doctrine (or observation) that "things" (or "everything", or "compound things") are impermanent (anicca).
I think that what we do with ("make sense of") the notion (of non-self) is maybe avoid "suffering" views like "I can't get what I want" and "I can't keep what I have" and "I am dying" and so on -- and maybe, instead, develop views that are closer to being true (or avoid "attaching" to any such views).
The question is, if there is no-self and no soul, then who is observing my thoughts?
It's conventional (in life and in language) to assume that there's an agent.
For example if you see some writing, you might assume that "someone" wrote it, to ask "who wrote this?" -- conventionally the existence of "the writing" proves (or implies) the existence of "the writer".
That's a dangerous generalisation though: if you see a creature, can you assume a creator?
Some people use logic like "The universe (also called "creation") exists, therefore God must have created it" -- but perhaps that's not a very provable, testable, and/or useful statement.
If you look at a rock, for example: did someone create it? Buddhism might say that "there were conditions as a result of which a rock exists" ... maybe many conditions including atoms, gravity , heat, time, wind and water ... but that's not the same thing as saying "there's a creator".
In the same way, the fact that there's "a thought" doesn't imply that there's "a thinker".
Am I wrong to say they are my thoughts?
I think this topic -- How is it wrong to believe that a self exists, or that it doesn't? -- suggests that it's unwise to do so.
Problems (suffering) arise with attachment, with craving, with "I"-making (having wrong views about self).
To some extent, I think that views are a matter of choice. For example perhaps I could choose to believe that my battery-power flashlight gives light because there's a demon or a god inside it, but I prefer not to (I think it wouldn't be a helpful belief).
Who am I?
I think the suttas define this question as the result of unwise attention.
For example here:

A thicket of wrong views
"There is the case where an uninstructed, run-of-the-mill person... does not discern what ideas are fit for attention, or what ideas are unfit for attention. This being so, he does not attend to ideas fit for attention, and attends instead to ideas unfit for attention... This is how he attends inappropriately: 'Was I in the past? Was I not in the past? What was I in the past? How was I in the past? Having been what, what was I in the past? Shall I be in the future? Shall I not be in the future? What shall I be in the future? How shall I be in the future? Having been what, what shall I be in the future?' Or else he is inwardly perplexed about the immediate present: 'Am I? Am I not? What am I? How am I? Where has this being come from? Where is it bound?'
"As he attends inappropriately in this way, one of six kinds of view arises in him: The view I have a self arises in him as true & established, or the view I have no self... or the view It is precisely by means of self that I perceive self... or the view It is precisely by means of self that I perceive not-self... or the view It is precisely by means of not-self that I perceive self arises in him as true & established, or else he has a view like this: This very self of mine — the knower that is sensitive here & there to the ripening of good & bad actions — is the self of mine that is constant, everlasting, eternal, not subject to change, and will endure as long as eternity. This is called a thicket of views, a wilderness of views, a contortion of views, a writhing of views, a fetter of views. Bound by a fetter of views, the uninstructed run-of-the-mill person is not freed from birth, aging, & death, from sorrow, lamentation, pain, distress, & despair. He is not freed, I tell you, from suffering & stress.
"The well-instructed disciple of the noble ones... discerns what ideas are fit for attention, and what ideas are unfit for attention. This being so, he does not attend to ideas unfit for attention, and attends [instead] to ideas fit for attention... He attends appropriately, This is stress... This is the origination of stress... This is the cessation of stress... This is the way leading to the cessation of stress. As he attends appropriately in this way, three fetters are abandoned in him: identity-view, doubt, and grasping at precepts & practices."

This answer, which uses "a rock" and "a flashlight" as an example, might imply a "materialist" view e.g. "people are only physical"; but I didn't mean that, it's defined as unwise to attach such a view ("this is my permanent Self, my eternal Soul") to anything, including the physical body.
It would also be a mistake to assume the doctrine implies that "nothing matters" -- it's an aspect of the doctrine, not the whole doctrine.


How can you use daily walks for spiritual growth in Diamond Way Buddhism?

From how I was taught, in Zen the best way to use daily walks for spiritual growth is to not use them for spiritual growth ;) In the true spirit of Parjnaparamita, forget about "spiritual growth" which is a very deluded motivation, and just walk.

From Karma-Kagyu perspective, I guess we can get into more details...

When you walk, it is very important to feel your entire body -- and not ignore any tension or tightness. The tension manifests in your posture and your gait, in how you hold your head-and-shoulders, your torso, your pelvis, how you put your weight down on your feet, what you do with your hands. When you feel comfortable, you can open up and your body parts can move more freely and be in harmony with each other. And vice versa - when you make your body and feet conveniently positioned - then your mind can feel comfortable. Imagine how a king or Buddha would walk, to us it looks like they walk "with pride". The reason they walk like that is because they always keep themselves very comfortable. They don't maintain negative stories and they don't maintain body tensions.

As you walk and see things, try not get caught up in stories. When you see something, if you habitually relate to it as "good" or "bad" then you no longer see it, instead you see your thoughts overlayed on top. Usually when we judge we judge on the basis of one or few "signs" or "marks" (nimitta - characteristic features that give us hints about qualities of the object). We then make inferences based on those signs and interpret what they tell us. This formula "marks => qualities => story" is what my last teacher called "preconception". They (preconceptions) come from our past experience. We then compare that story with how things are supposed to be in the perfect case. And then we evaluate it as "good" or "bad" - and we feel corresponding emotion. When this happens we no longer see things as they are, we only see the "signs" and the "story" colored with some feeling. Instead, when you don't let this mechanism go on autopilot, then you see things more fully - you see many other aspects than just signs, your experience becomes much more rich and nuanced. In Buddhism we say you see things "as they really are".

Same thing happens if seeing some things or some people makes you judge yourself. This happens in two cases. Either you see something or someone that you evaluate as "very good" - and then you start comparing it with yourself and come to a conclusion that since you are not "so good" - then you must be "bad". Or there is a case when you imagine how someone must be seeing you from their perspective and you imagine what they probably think about you (awesome/worthless, smart/dumb, handsome/ugly etc.) There are many variations of these - but basically they all involve some comparison and imagination. So again, instead of feeling yourself as being fully yourself - you are making up some story in your head. Needless to say, when this happens you usually lose the sense of your body and posture/shoulders/lower back/pelvis/feet. Instead, when you don't alienate (deny, disown) yourself and you allow yourself to be natural/uninhibited/spontaneous, we say you become "an authentic person" or a "true person".

So the idea with walking meditation is to get out of your head and just walk, walk while seeing the world in all its multifaceted colors, and while feeling you are who you are with all your various qualities - without getting caught in those imaginary stories.

Of course, when you walk you don't need to think about any of this - you just walk comfortably and look around. It's the simplest thing in the world.


the five precepts and marijuana - does marijuana count as an intoxicant?

Yes. Marijuana is an intoxicating substance.
From AccessToInsight.org's The Five Precepts: pañca-sila:

Suramerayamajja pamadatthana veramani sikkhapadam samadiyami
I undertake the precept to refrain from intoxicating drinks and drugs
which lead to carelessness.

It comes from the suttas e.g. AN 8.39.
The reason for abstaining from alcohol, drugs and any other intoxicating substances is explained below. It's because intoxicating substances cause heedlessness and moral recklessness, and results in one breaking the other four precepts, because a person's best judgment is impaired under the influence of intoxicating substances.
However, if intoxicating substances are consumed in a strictly controlled way as a medicine, administered by a medical professional, then it is ok. For e.g. I have heard that psilocybin has been used for treating severe depression.
From the essay "A Discipline of Sobriety" by Ven. Bodhi (the highlighted statements apply to both alcohol and drugs):

For his lay followers the Buddha has prescribed five precepts as the
minimal moral observance: abstinence from killing, stealing, sexual
misconduct, false speech, and the use of intoxicants. He did not lay
down these precepts arbitrarily or out of compliance with ancient
customs, but because he understood, with his omniscient knowledge,
which lines of conduct lead to our welfare and happiness and which
lead to harm and suffering. The fifth precept, it should be stressed,
is not a pledge merely to abstain from intoxication or from excessive
consumption of liquor. It calls for nothing short of total abstinence.
By this rule the Buddha shows that he has understood well the subtle,
pernicious nature of addiction. Alcoholism rarely claims its victims
in a sudden swoop. Usually it sets in gradually, beginning perhaps
with the social icebreaker, the drink among friends, or the cocktail
after a hard day's work. But it does not stop there: slowly it sinks
its talons into its victims' hearts until they are reduced to its
helpless prey.
To dispel any doubt about his reasons for prescribing this precept,
the Buddha has written the explanation into the rule itself: one is to
refrain from the use of intoxicating drinks and drugs because they are
the cause of heedlessness (pamada). Heedlessness means moral
recklessness, disregard for the bounds between right and wrong. It is
the loss of heedfulness (appamada), moral scrupulousness based on a
keen perception of the dangers in unwholesome states. Heedfulness is
the keynote of the Buddhist path, "the way to the Deathless," running
through all three stages of the path: morality, concentration, and
wisdom. To indulge in intoxicating drinks is to risk falling away from
each stage. The use of alcohol blunts the sense of shame and moral
dread and thus leads almost inevitably to a breach of the other
precepts. One addicted to liquor will have little hesitation to lie or
steal, will lose all sense of sexual decency, and may easily be
provoked even to murder. Hard statistics clearly confirm the close
connection between the use of alcohol and violent crime, not to speak
of traffic accidents, occupational hazards, and disharmony within the
home. Alcoholism is indeed a most costly burden on the whole society.
When the use of intoxicants eats away at even the most basic moral
scruples, little need be said about its corrosive influence on the two
higher stages of the path. A mind besotted by drink will lack the
alertness required for meditative training and certainly won't be able
to make the fine distinctions between good and bad mental qualities
needed to develop wisdom. The Buddhist path in its entirety is a
discipline of sobriety, a discipline which demands the courage and
honesty to take a long, hard, utterly sober look at the sobering
truths about existence. Such courage and honesty will hardly be
possible for one who must escape from truth into the glittering but
fragile fantasyland opened up by drink and drugs.
It may well be that a mature, reasonably well-adjusted person can
enjoy a few drinks with friends without turning into a drunkard or a
murderous fiend. But there is another factor to consider: namely, that
this life is not the only life we lead. Our stream of consciousness
does not terminate with death but continues on in other forms, and the
form it takes is determined by our habits, propensities, and actions
in this present life. The possibilities of rebirth are boundless, yet
the road to the lower realms is wide and smooth, the road upward steep
and narrow. If we were ordered to walk along a narrow ledge
overlooking a sharp precipice, we certainly would not want to put
ourselves at risk by first enjoying a few drinks. We would be too
keenly aware that nothing less than our life is at stake. If we only
had eyes to see, we would realize that this is a perfect metaphor for
the human condition, as the Buddha himself, the One with Vision,
confirms (see SN 56:42). As human beings we walk along a narrow ledge,
and if our moral sense is dulled we can easily topple over the edge,
down to the plane of misery, from which it is extremely difficult to
re-emerge.
But it is not for our own sakes alone, nor even for the wider benefit
of our family and friends, that we should heed the Buddha's injunction
to abstain from intoxicants. To do so is also part of our personal
responsibility for preserving the Buddha's Sasana. The Teaching can
survive only as long as its followers uphold it, and in the present
day one of the most insidious corruptions eating away at the entrails
of Buddhism is the extensive spread of the drinking habit among those
same followers. If we truly want the Dhamma to endure long, to keep
the path to deliverance open for all the world, then we must remain
heedful. If the current trend continues and more and more Buddhists
succumb to the lure of intoxicating drinks, we can be sure that the
Teaching will perish in all but name. At this very moment of history
when its message has become most urgent, the sacred Dhamma of the
Buddha will be irreparably lost, drowned out by the clinking of
glasses and our rounds of merry toasts.


Not getting what one wants as a good thing or something to be thankful

Certainly not getting what you want is unsatisfactory. This is Dukka Dukka. I will not say this is a good thing though this kind of thought can help you emotionally. Sometimes it might be true that not getting something may be better as you might be blinded by craving as not to see the downside e.g. a partner lower in morals.

Even if you get what you want this is not satisfactory as you have to part with it at some point.

The root cause of craving is sensations experienced then in contact with the object that you want or mental satisfaction in owning it (has come into the spear of mine).

If you don't get something wanted then the sensation you experience is painful. You have to look at it as impermanent or if you are developed in meditation as arising and passing of sensations (phenomena which is experienced or felt). By doing this you are weakening your root of aversion.

When you experience satisfactory experiences you have to look at the sensations again equnimously. When you experience the pleasantness passing away do the same. This is because doing so weakens the root of craving.

When you experience neutral sensations, the process of fabrication continues. Use this as means to eradicate your ignorance. Neutral sensations are unsatisfactory since we still have conditioned existence.

By reaction to sensations you create craving. Carving with further thinking and pondering and conpept polifration  creates clinging. At this point you will be planning on how to aquire what you want. If you miss de railing the train at feeling this is the next place you can try this by developing mastery over the mind. This is nothing wrong working towards getting what you want within the framework of morality and right livelihood. But in doing so you should try to be equanimous as possible to sensations and try developing more mastery over the mind to prevent craving and clinging.


Does any canonical sutta say you can attain enlightenment *while* chanting?

I posted an answer here, over at Sutta Central Forum:

... in the Aṅguttara Nikāya The Book of the Fives, Sutta 26, "Liberation", the "five bases of liberation" are listed.
Number three is "Reciting the Dhamma". The pali term for "Reciting" is "sajjhāyaṃ karoti", which can also be translated as "chanting", however the chanting referred to here must be deeply understood by the one chanting. That is to say, the type of chanting here is not as in incanting a mystical, magical spell in an arcane language, where you don't know what the words mean, where the power is inherent to the sound of the words.


By asking if a person or someone reaches Nibbana is implying that people/persons exist meaning that one is not dealing with ultimate reality but instead with conventional reality.

In ultimate reality there is no person or being that gets enlightened.

Take the "i, me, you, him, her, it" out of the sentence and just observe what is left -> Enlightenment happens. Enlightenment is reached.

The unconditioned, Nibbana cannot be understood by conditioned language or logical reasoning. In other words the unconditioned cannot be grasped or understood by using tools from the conditioned realm.

The unconditioned must be experienced and comprehended through insights into reality.

If another view is taken which is that when enlightenment happens the self is destroyed, that view is flawed too. Why? Because there didnt exist a self in the first place so there is nothing that gets destroyed. Instead what happens is that it is realized through insight meditation that a self is nowhere to be found.

In this book "What Buddhists Believe" by Ven. K. Sri Dhammanda, on p. 70-74 there is a chapter about what happens to a Buddha after death. Its a conversation between the Buddha and Ananda where 4 propositions are mentioned. They are;

A Tathagata exists after death;
A Tathagata does not exist after death;
A Tathagata exists and yet does not exist after death;
A Tathagata neither exists nor does not exist after death’

A Tathagata is a Buddha. You can read a bit more about the meaning of the word here.

Lanka


Could someone provide a list of all Buddhist schools?

Out of thousands schools, sub-schools, and hybrids, here are some of the most notable outlines:

Early Buddhism and conservative descendants

=======Popular wing=======

Mahasanghika (developed into Mahayana)

Gokulika (in Varanasi/Pataliputra)

Bahusrutiya (in Kosala)

Satyasiddhi / Tattvasiddhi (Chinese, extinct)

Jojitsu (Japanese)

Prajnaptivada (in Magadha)

Lokottaravada
Caitika

Pudgalavada heresy (extinct)

Vatsiputriya (extinct)

Sanmitiya (extinct)

=======Conservative center=======

Tamraparniya (the Sri Lanka offshoot)

Theravada

Mahisasaka (absorbed into Theravada)
Dharmaguptaka (in Gandhara, extinct)

Ritsu (Japanese)

=======Abhidharma wing=======

Sarvastivada (in Gandhara, extinct)

Vaibhashika (extinct)
Sautrantika (developed into Yogacara)
Kusha (Japanese, extinct)

Mahayana

=======Prajnaparamita / emptiness group=======

Yogacara line

Faxiang (Chinese)
Hosso (Japanese)

Madhyamaka line

Tibetan family

Kadam (extinct)

Gelug (Dalai Lama's school)

Sakya

Sanlun (Chinese, extinct)

Sanron (Japanese, extinct)

Chan (Chinese)

Zen (Japanese)

Soto
Rinzai

Fuke (extinct)

Obaku

Seon (Korean)

Jogye / Chogye (my Zen Master's school)

Thien (Vietnamese)

=======Tantric group=======

Tibetan tantra

Nyingma

Aro gTér

Kagyu

Karma-Kagyu (Chogyam Trungpa's school)

New Kadampa (Gelug breakaway)

Tangmi (Chinese)

Shingon (Japanese)

=======Sincretic group=======

Bon-Nyingma hybrid (Tibetan)
Shugendo (Japanese)
Ari Gaing (Burma, extinct)
Newar (Nepal)

=======Popular wing / Ekayana=======

Pure Land / Amitabha line

Jodo (Japanese)
Yuzu Nembutsu (Japanese)

Lotus Sutra line

Tiantai (Chinese)

Cheontae (Korean)
Tendai (Japanese)
Nichiren (Japanese)

Nipponzan-Myohoji (my first encounter with Buddhism)

Avatamsaka Sutra line

Huayan (Chinese)

Kegon (Japanese)
Hwaeom (Korean, subsumed by Seon)


Killing a parent and killing a foster parent

Killing a normal human being itself is a serious bad karma. So while killing a foster parent is not an Ananthariya Karma, it is still a severe bad karma depending on how good he/she was.


Food and other cravings, and guarding the senses

I feel like concentrating on impermanence and on the disadvantages, in
  the midst of an emotion, works not as effective.

Yes, that's because what impermanence is not the one and only thing which need to be considered to uproot the cravings. No matter how hard you try can you get satisfied with any kind of cravings? It can be food. If you are fully satisfied or
if you've reached ultimate satisfaction would you need to eat food again? No right. Our mind always looking for this satisfaction and it always get cheated by things like nice / delicious food etc. And then we keep running after that. It's true we feel happy when we eating that, but those doesn't full fill our mind's expectation of ultimate satisfaction. Why is that? That's because everything in this world is insatiable. That's the reality | truth of this world. Impermanence is just a one quality / attribute of that nature. Once you realise this, you should think twice before running after mirages. Because no matter how hard you run you won't be satisfied only thing you get is the tiredness and other occurrences while running. And then you should see danger of those kind of actions. Not knowing the gratification (assada), the danger (adinava) and how to escape from (nissarana) are the root causes for cravings. When you think about this and when you realise the uselessness of cravings it will start to get reduced.

  I read the Buddha saying about guarding the senses -- but I doubt that
  the Buddha meant not looking, not hearing (etc) at things.

Again this links to the above. How you guard your senses is thinking about the uselessness of those by knowing the gratification (assada), the danger (adinava) and how to escape from (nissarana). This doesn't mean that not looking at things but controlling the attachment / craving / gratification (assada) towards the thing you look at and the action of looking by thinking of danger. Which will realise you the gratification (assada), the danger (adinava) and how to escape from (nissarana) the thing you looked at and the action of looking. And finally you start to escape from the part of attachment or the gratification of that. Because that's what drives you towards the danger.

If you think about the bait given to a fish. Is the food in the bait given pain to the fish? or the hook (used to catch the fish with the fishing rod) given the pain?

If you the answer is hook, then if you just place the hook without the food (bait) does the fish get caught or the fish get pain?

No right. Then if you think deeply you will understand that the food (bait) is given pain to the fish. Like wise gratification (assada) gives the danger (adinava) to us. We can't blame fish because it doesn't know that it's a trap. It's called Avidya (ignorance). For us it's the same. Poor us! we are covered with Avidya (ignorance) so we don't realise the truth, we don't realise it's a trap, and we get attached to things and keep running after gratification (assada) of those, thinking those will give us ultimate satisfaction. But it will never happen. Because the world is insatiable. Once you see this you will find a
to escap (nissarana) from gratification (assada). Don't misunderstand this escape is not from the outer world things, but from the attachment / cravings.

Where does the ultimate happiness and satisfaction actually do exist, which is looking for by our minds? -> It's called Nivana, Nirvana or Enlightenment

With Metta..!


Can the noble eightfold path be followed in its entirety by a lay follower?

At a higher level the 8 fold path consists of 3 fold training:

Development of morality
Development of control or mastery over the mined
Development of knowledge of the reality pertaining to one's mind and cognitive process

There is nothing in the above which a lay person cannot develop or not reap benefits by developing.

Being a monk you have less responsibilities hence more time to practice. The key is to practice regardless of whether you are lay or a monk.


AI is a concept. Not a reality. AI in essence is simply electrified hardware.
A computer is Rupa. Electricity is Rupa. There has to be Nama involved to talk about rebirth or having a consciousness. A computer might beat a man in Chess. But it's still just matter. No mind involved.


Did Shakyamuni Buddha say anything in regard to fear

In the Cātumā Sutta (Majjhima Nikāya, 67) Buddha talks about four types of fear in the case of Bhikkus just as there are dangers and hazards in a sea like stormy waves, crocodiles, whirlpools, and sharks. Those four fears were temper (ill will against those who instruct them and guide them); gluttony (dissatisfaction with training rules such as those concerning taking of meals), women and pleasures of senses.
(http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2010/02/34.7-Catuma-S-m67-piya.pdf)
Also Buddha spoke of four reasons as to why we fear death. They are:  attachment to the body,  attachment to sensual pleasures; knowledge that we’ve done cruelty to others and the resulting fear that after death we’ll have to face consequences for it,  and lastly the fear of not having seen the true Dhamma, or for still having doubts about its truth.
Then in the Sangaha Bala Sutta, (The Discourse on the Powers (in connection with conciliation) Aṇguttara Nikāka  9.5)  Buddha talks about how to free yourself from five common fears.
http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/2.21-Sangaha-Bala-S-a9.5-piya.pdf
Those five fears are the fear of livelihood; ājīvika bhaya (2) the fear of disrepute; asiloka bhaya (3) the fear of nervousness before an assembly; parisa,sārajja bhaya (4) the fear of death; and maraṇa bhaya (5) the fear of a bad destiny [rebirth]. duggati bhaya
Another Sutta that talks about fear is  ‘Pancha Bhayavera Sutta’ or the discourse on the five fears and hates. [Disadvantages of breaking the Five Precepts] (Anguttara Nikaya  5.174)
http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/6.4-Vera-S-a05.174-piya.pdf
A noble disciple will overcome these five factors that caused fear and hate. The first is to abstain from killing. The second is to abstain from stealing. The third is to abstain from wrongful sexual conduct. The fourth factor is to abstain from falsehood. The last factor is to live refraining from intoxicants.
The Dutiya Anagata-bhayani Suttam (The Discourses on Future Dangers )  is another of interest:
http://obo.genaud.net/dhamma-vinaya/ati/an/05_fives/an05.078.than.ati.htm

"Monks, these five future dangers, unarisen at present, will arise in the future. Be alert to them and, being alert, work to get rid of them. Which five? …
"There will be, in the course of the future, monks undeveloped in body,[1] undeveloped in virtue, undeveloped in mind, undeveloped in discernment. They — being undeveloped in body, undeveloped in virtue, undeveloped in mind, undeveloped in discernment — will give full ordination to others and will not be able to discipline them in heightened virtue, heightened mind, heightened discernment. These too will then be undeveloped in body... virtue... mind... discernment. They — being undeveloped in body... virtue... mind... discernment — will give full ordination to still others and will not be able to discipline them in heightened virtue, heightened mind, heightened discernment. These too will then be undeveloped in body... virtue... mind... discernment. Thus from corrupt Dhamma comes corrupt discipline; from corrupt discipline, corrupt Dhamma.


Not understanding Jhana Mastery Of Reflection?

Pa-auk monastery tradition:

If you ask this question at pa-auk, they will recommend "you should in meditation, first". Because mind and mind factors arising are very fast and complex. So, it is not possible for no-attained-jhāna-person to clearly understand jhāna factors. And I am agree with that recommend, too.

This image captured from TEACHING & TRAINING book of Pa-auk monastery:

From path of purification pāli, pathavīkasiṇaniddesa:

  ayaṃ panettha atthappakāsanā, paṭhamajjhānato vuṭṭhāya paṭhamaṃ vitakkaṃ āvajjayato bhavaṅgaṃ upacchinditvā uppannāvajjanānantaraṃ vitakkārammaṇāneva cattāri pañca vā javanāni javantiฯ tato dve bhavaṅgāni, tato puna vicārārammaṇaṃ āvajjanaṃ, vuttanayāneva javanānīti evaṃ pañcasu jhānaṅgesu yadā nirantaraṃ cittaṃ pesetuṃ sakkoti, athassa āvajjanavasī siddhā hotiฯ

Translation:

Emerges 1st jhāna, then...
Bhavaṅga-minds auto arising, break it, then ...
Thinking of vitakka by only 4-5 javana-minds arising, then...
Agree only 2 bhavaṅga-minds arising, break it, then...
Thinking of vicāra by only 4-5 javana-minds arising, then...
Loop 4-5 steps by 5 jhāna-elements' sequence, until you will attain Jhana Mastery Of Reflection.

How to notice the Jhana Mastery Of Reflection attainment?

General person use 7 javana-minds arising   per thought and uncountable bhavaṅga arising between thought, but the jhāna-master must use lesser javana-minds and lesser bhavaṅga-minds to take mastery jhāna.

The practitioner attained right, exact  Jhana Mastery Of Reflection, when he can meditate  Jhana Mastery Of Reflection follow above step without any getting struck, such as more than 2 bhavaṅga-minds arising or more than 4-5 javana-minds arising.

Still doubt?

There are many jhāna masters at Pa-Auk Forest Monastery. This is better way, because below quote was written in the path of purification page 94:

  So if someone with cankers destroyed is available, that is good. If
  not, then one should take it from a non-returner, a once-returner, a
  stream-enterer, an ordinary man who has obtained jhána, one who knows
  three Piþakas, one who knows two Piþakas, one who knows one Piþaka, in
  descending order [according as available]. If not even one who knows
  one Piþaka is available, then it should be taken from one who is
  familiar with one Collection together with its commentary and one who
  is himself conscientious. For a teacher such as this, who knows the
  texts, guards the heritage, and protects the tradition, will follow
  the teachers’ opinion rather than his own. Hence the Ancient Elders
  said three times, “One who is conscientious will guard it.”

For alternative translation see:

https://buddhism.stackexchange.com/a/23977/10100

For word definition:

http://www.palikanon.com/english/sangaha/chapter_1.htm
http://www.palikanon.com/english/sangaha/chapter_2.htm
http://www.palikanon.com/english/sangaha/chapter_3.htm
http://www.palikanon.com/english/sangaha/chapter_4.htm
https://www.accesstoinsight.org/lib/authors/nanamoli/PathofPurification2011.pdf


What does 'passing away of dhamma' mean in Satipatthana sutta?

The materialistic mindset invented language built around the key notion of objects. Objects are represented by nouns.
In contrast to that, the spiritual mindset or the mind-over-matter mindset came up with the concept of dharma as its primary building block. Dharmas are not nouns because they are not objects. Instead, dharmas are adjectives because they represent qualities.
In the mind-first view of existence, the primary building block is an experienced quality, a dharma.
Dharmas arise into existence, stay for some time, and then disappear. Most dharmas don't arise momentarily but gradually form from some combination of previous dharmas. Then they mutate or change, often weakening over time. Eventually they vane away or gradually decompose and become components for other dharmas.
All dharmas, practically speaking, with some rather theoretical  exceptions, are transient. This is because, being nothing but qualities of combinations of other qualities they morph away out of existence as their underlying qualities morph away as their underlying qualities morph away and so on.
When Buddha describes meditation on arising and passing away of dharmas, he is referring to gradual formation, deformation, and eventual morphing out of existence of all qualities observable by the meditator.
This includes so-called external qualities, and so-called internal qualities. "External" qualities include shape, size, color, loudness, pitch, smell, temperature etc. - morphing in and out of existence either quickly or slowly. "Internal" qualities include discursive, emotional, somatic, conceptual, abstract, intuitive etc. characteristics, morphing in and out of existence. Qualities in both groups arise and vane due to forces out of our control (such as the time passing) as well as due to forces in our control (such as us moving our gaze or our attention around).
This is what's called "arising and passing away of dhammas".
Specifically in context of Satipatthana the external dhammas are analyzed by their sensory basis (visible, audible, tactile  etc) and the internal dhammas are analyzed by their effect on one's practice. The most important dhammas to watch are the qualities of mind that help or harm meditation, such as sensuality, negativity, torpor, anxiety, uncertainty, as well as the positive qualities such as mindfulness, determination, enthusiasm, focus, calmness etc.
The most abstract method of contemplating the qualities is by observing the Noble Truths in action, happening in front of one's very eyes. "This is the quality of dukkha (i.e. ~painful aspect of some experience) arising, this is the underlying quality of craving, here the quality of craving has been abandoned, here the dukkha quality is no longer to be found."


Is their any books where the collection quotation of Milarepa are available?

In French: “Milarépa - Oeuvres complètes, La vie, Les cent mille chants” translated from Tibetan by Marie-José Lamothe, Fayard, ISBN 978-2-213-62897-4
As far as I know, it’s not available in English.


How does one know if one is destined to attain Nibbana?

Traditionally, one hears it from one's teacher (Buddhist mentor). For example, my Zen master once said, pointing at me, "One day this guy will get everything. He will be Bill Gates". This is known as "the prediction".

Even without that, the teachings say, if you are committed to figure it out, however slowly, you will get there sooner or later.

This abstract idea that Nibbana is actually within reach gets concrete and personal only at pretty advanced stages. Basically, once you clearly see the mechanism of conflict/suffering and how it all works, and not just see but get some grasp of mastering unconditional "rightness", that's when you know you will get there with time.


Buddhist master, Ajahn Brahm, answered a similar question as follows in an interview with Rachael Kohn:

  Rachael Kohn: I know that your message is often about happiness, and how the point of life...is all about changing one’s attitude, not
  really about changing the world. And yet you would know that that kind
  of an attitude can also be breeding a certain indifference to the
  world...Does Buddhism ever teach a resistance to things which are
  dangerous, which are bad, which are evil?

  Ajahn Brahmavamso: Yes, we teach a resistance to anger, we teach a resistance to jealousies, we teach a resistance to stupidity. Those
  are the things which we should really be resisting, you know, the
  anger and the feelings of revenge, the hurt, the grief, the guilt
  inside of us, all those negative emotions which make our world. Those
  are the things which we want to resist, to understand, to overcome, by
  letting go.

In other words, Buddhists claim that harm in this world arises because of greed, hatred, and delusion; they seek to eliminate these sources of harm within themselves and to educate others so that they may do the same. So, on this view, Buddhists are addressing the root causes of suffering in themselves and others and helping people in this way--the most effective way. As the passage above implies, an ideal Buddhist is far from passive internally and, although she may appear to be so externally, one could argue that she is simply skillful/technical in her approach to the suffering of others.

In summary, Buddhists want to use wisdom, rather than money and power, to help others. According to them, this is the most effective way to do so, and the only way to get to the cause of the problem; using power and money to alleviate worldly problems can be a temporary, palliative solution at best. The Buddha often compared himself to a doctor, treating the causes of suffering rather than exclusively treating the symptoms.


Is it possible to see the counterpart sign (nimitta) with eyes open?

The proof of the pudding is in the eating, no matter how many books are written about the pudding. Once eaten there can be no mistake about it.

As a samatha meditator, both the signs exist for both types of meditation and which still appear when the eyes are open if they are vivid.

Having said that I've quiet a few  fellow  meditators who do not see the signs but continue to develop Jhanas using feeling.


I wondered if there was a consciousness that underwent nirvana?

According to the Theravada abhidhamma, yes, it is called a lokuttara-citta, and it is beautiful (sobhana).

  Is there a consciousness of nirvana?

This wording is a bit more difficult to answer. Since nirvana entails unbinding of consciousness, it is hard to describe it as being conscious of anything. Still, technically the mind is said to take nirvana as an object; it is probably better phrased as "object of focus", as in "the mind is focussed on/in unbinding", rather than "the mind is conscious of nirvana" - the latter is a bit of an oxymoron, I think.

  Is there a consciousness that creates either of these consciousnesses?

"creates" is a bit problematic. lokuttara minds are said to be unconditioned, yet there is clearly a process that leads to them, and that process clearly involves certain specific minds - namely, the mind that realizes the first and second noble truths.  There is a consciousness that is necessary for the attainment of nirvana; I don't think this exactly means that said consciousness "creates" the nirvana consciousness. It is all very technical. In practice, nirvana is the unbinding, so any talk of creation and arising is very much out of place.


I think there is no perfect formula for a book. Different approaches apply to different target audiences for different objectives.

Even some of Ajahn Brahm's non-technical books of humor and anecdotes (like "Don't Worry, Be Grumpy") are useful to certain types of audience who need to have their negative emotions soothed, while being treated to subliminal doses of the Dhamma.

I personally would like to see a book that can reach out to Buddhists and non-Buddhists alike, help them, and invite them to look at Buddhist teachings more deeply.

Non-Buddhists usually know about Buddhism's first noble truth about suffering. They also tend to be aware about the focus on meditation as a technique to reach enlightenment. Recent advancements in mental healthcare have taken at least a part of Buddhist mindfulness for treating depression, anxiety and coping with chronic pain. This has made Buddhism more popular.

However unfortunately, many non-Buddhists still think it's a depressing religion that shuns the material world and relationships, and exhorts people to become monks who meditate all day to become stoic and unemotional.

On the other hand, Buddhists who are not well-aware of the Dhamma, tend to focus on attending ten-day meditation courses and trying out meditation techniques without understanding what they are ultimately meant for. Furthermore, without improving their virtues (sila) and personal habits, meditation may not be useful as the five hindrances would continually beset them.

From my study of the suttas, I feel that there is a huge part of the Dhamma that can benefit both groups. This would be what I call "wholesome living and skillful thinking" or an application of Buddhism into psychology for laypeople.

Such a book would explain mindfulness, heedfulness, virtues (sila), dealing with addiction, anger management etc. For e.g. this question (and this follow-up question) on Buddhism.SE asked about how to deal with the arising of contempt towards other people. A book on wholesome living and skillful thinking would relate contempt to aversion and delusion, and may suggest the reader to overcome contempt with compassion through understanding the background and underlying situations behind the behavior of other people.

I would also like to see this book explaining concepts of skillful thinking using simple non-technical terms with anecdotes and practical examples. However, it should also include copious references from the suttas to support its arguments, as that would invite both Buddhists and non-Buddhists to look into the suttas more deeply, as a source of inspiration for daily living.

Managing relationships, finances, career etc. should also be covered in this book.

Overall, this book should give readers the impression that Buddhism guides Buddhists, non-Buddhists, laypeople and monks alike towards cultivating short term, medium term and long term happiness on the journey towards the complete cessation of suffering, through wholesome living and skillful thinking. The book should also portray the Buddha as a pragmatic master psychologist, through his own words from the suttas.

It may also be useful if the book focuses only on a few core techniques like letting go (by not clinging onto incoming stimuli), reframing (for example, meditating on unattractiveness to overcome lust), compassion (i.e. understanding the reason for, and trying to reduce, the suffering of others) and so on.


the parable of the good samaritan
The parable of the Good Samaritan isn't about "special responsibility to those we have injured". In the parable:

The "certain man" was injured by robbers (who stripped and beat him)
The injured man was ignored by a priest and a Levite
The Samaritan showed compassion and acted as if he had a special responsibility (even though the Samaritan had nothing to do with, wasn't responsible for, causing the man's injury)
Jesus's message is to do like the Samaritan did

'Mercy' can be defined as compassion or forgiveness shown towards someone whom it is within one's power to punish or harm.
You seem to be interested in the definition of "mercy".
I slightly disagree with your definition above. If you're able to rescue someone from drowning, for example, then that could an act of mercy, but (assuming you weren't the cause of their being in the water) nothing to do with "punishing" or "harming".
You might like Wikipedia's article on Mercy (I went to it to look for the etymology of the word). An interesting part is at the end,

To be mercy, the behavior generally can not be compelled by outside forces. A famous literary example that alludes to the impact of the ethical components of the mercy on the legal aspects is from The Merchant of Venice when Portia asks Shylock to show mercy. He asks, "On what compulsion, must I?" She responds:

The quality of mercy is not strain'd.
It droppeth as the gentle rain from heaven
Upon the place beneath. It is twice blest:
It blesseth him that gives and him that takes.

That almost argues against your definition: because there might be some special obligation towards someone you have injured.
The corresponding traditional Buddhist virtues, by the way, if you want to research them further, might be the Brahmaviharas (including Karuṇā which is 'translated' as compassion), and ahimsa (harmlessness or non-violence, for example mentioned here).

compassion towards someone who you have punished or harmed
There may be something somewhere in Buddhist scripture, that talks about whether and how to behave towards people you have injured.
Although that's your question I'm not immediately inclined to answer it, because the more important message of Buddhism is, "because you have compassion for people, do not cause them injury".
The basic rules of conduct, for example the five precepts, and the ethical conduct portion of the eight-fold way, are to do with not causing injury.
One of the suttas about the five precepts starts with,

There are these five gifts, five great gifts — original, long-standing, traditional, ancient, unadulterated, unadulterated from the beginning — that are not open to suspicion, will never be open to suspicion, and are unfaulted by knowledgeable contemplatives & brahmans. Which five?
There is the case where a disciple of the noble ones, abandoning the taking of life, abstains from taking life. In doing so, he gives freedom from danger, freedom from animosity, freedom from oppression to limitless numbers of beings. In giving freedom from danger, freedom from animosity, freedom from oppression to limitless numbers of beings, he gains a share in limitless freedom from danger, freedom from animosity, and freedom from oppression. This is the first gift, the first great gift — original, long-standing, traditional, ancient, unadulterated, unadulterated from the beginning — that is not open to suspicion, will never be open to suspicion, and is unfaulted by knowledgeable contemplatives & brahmans...

The practice of Dana (i.e. gift-giving or generosity) is made especially by laypeople towards monks and nuns; and not because those monks and nuns were injured by the laypeople.

Because it seems to me to be the bedrock of intelligent ethics
Some people think that the "golden rule" is the bedrock of intelligent ethics, e.g. "do unto others as you would have others do unto you", also known as "love thy neighbour as thyself".
I think you'll find that in Buddhism too, for example in the Dhammapada,

All tremble at violence; all fear death. Putting oneself in the place of another, one should not kill nor cause another to kill.

All tremble at violence; life is dear to all. Putting oneself in the place of another, one should not kill nor cause another to kill.

One who, while himself seeking happiness, oppresses with violence other beings who also desire happiness, will not attain happiness
hereafter.

One who, while himself seeking happiness, does not oppress with violence other beings who also desire happiness, will find happiness
hereafter.

Speak not harshly to anyone, for those thus spoken to might retort. Indeed, angry speech hurts, and retaliation may overtake you.

Did the Buddha ever teach that we have a special responsibility to those we have injured?
I'm pretty sure he taught that we have some responsibility to not injure people.
I think that the practice of deliberately (intentionally) injuring someone would be likely to have a negative/undesirable karmic consequence.
I'm not sure it's always possible to undo an injury (which is a reason for avoiding causing injury in the first place).
Answers to other topics on this site, for example What do we do when we've broken a precept?, don't seem to focus on restitution or special responsibility towards the injured party.
The practice of the Buddhist "Metta Bhavana" (or "cultivation of loving-kindness") meditation is meant to develop compassion towards all people, both near and far, both more dear and less dear -- and not especially towards "someone you have punished or injured".


Pali scriptures were brought down by the Sangha who actively practice the teachings of the Buddha. The oral tradition and later the scriptures were verified by many Buddhist councils which were headed by enlightened monks. These councils were held specifically to eliminate alien elements.

Folklore is just stories told by ordinary householders who might not even be Buddhist. ex: Hindus believe that Buddha is an avatar of one of their Gods


Question on the possibility of higher rebirth for animals

No, you can't transfer merits to animals. You can only do that with a class of Petas(hungry ghosts) called the 'Paradattupa-jivi'. Animals at best might hear some Dhamma, memorise it and as a result be born in a better place next life. But that is extremely rare. Animals don't get stuck endlessly in the animal realm. They can easily sink lower and get into more extreme states of suffering. Once their bad karma has been exhausted, a past good Karma may come forward to give them a better life.

There is a classification of Karma, according to the priority of effect:

WEIGHTY (GARUKA) KARMA.
PROXIMATE (ASANNA) KARMA OR DEATH-PROXIMATE KARMA
HABITUAL (ACCINA) KARMA
RESERVE OR CUMULATIVE (KATATTA) KARMA

Katatta Kamma are usually the Kamma done in past lives. So if #1,#2,#3 are missing, Katatta Kamma will get a chance to result in the next birth. But that is highly unlikely as animals mostly have habitual and proximate Kammas. So the chances are that they will keep sinking lower. But once you get into the Niraya, you probably won't be creating any new significant Kamma. Because you will be in a constant state of agony throughout the lifespan.


My understanding is that, that's the only world available until new world system starts forming, and they start falling down again.

So you can say we all have a little bit of respite but once in a kalpas, not much isn't it.


In the Tibetan book of the dead, Chapter 2, what is the significance of NOT renouncing the 3 poisons

Not renouncing the three poisons is considered a foundational prelude to the journey, that the practitioner develops a recognition and respect of the function of the three poisons - which comes about as one reads and gives further practice - and that, in this graduated development, grows the clear seeing of liberation. By this very seeing, the three poisons dwindle and waver of their own tender, and not through the recourse of any self-governing motivations which are, by and large, etched with the three poisons, marred by them. Thus, the relinquishment of the three poisons occurs naturally.
Therefore, recognition and respect of the three poisons is something that grows through persistence. If I understand him correctly, Andrei Volkov mentioned - indirectly - that they simply present as growing pains that are transmuted into compassion where he refers to the three poisons in their greater domain, as samsara.

The transformed purified attitude to samsara is called "compassion" or
"unity of wisdom and compassion". You still see all those childish
behaviours, neuroses etc. but you see them as growing pains, as part
of an evolution. You see that in the grand scheme of things everything
is perfect and is going as it's supposed to. At that point you can try
and help as much as you can, but you also have patience to let things
develop naturally.
See more here

In some respect, renouncing the three poisons is to renounce liberation in and of itself.


Why is the Yogācāra school called 'mind only'?

To fill out R Barzell's comment more and to venture my own answer in the hope of being corrected. It seems like the most satisfying explanation of this is from this source

  the reality we think we perceive does not exist except as as a process
  of knowing. Phenomena, anything that can be experienced, have no
  reality in themselves. At the same time, there is no "experiencer" who
  experiences except as a process of mind.

My further understanding of this though is that the Yogācāra school was a very practically based school and any philosophical discussions would have been secondary to meditation and personal enquiry so this kind of statement would have been provisional on this. This would contrast with the rival Madhyamika school which had a greater emphasis on philosophical discourse. Peter Harvey in an Introduction to Buddhism (pp129 2nd Edition) says of this

  Madhyamika has an analytical, dialectical approach [...] emphasizing
  wisdom; the Yogacara's emphasized samadhi (meditative concentration)


What happens to grasping at 'self' after termination of life?

In case one, there is re-birth - hence he continues with grasping.
In the second case (for an Arahant), there is no rebirth.


Is shellfish aquaculture considered a wrong livelihood?

The Vanijja Sutta is the standard definition of "wrong livelihood" and is, as you saw, not specific. It says, in its entirety (at least in this translation),

"Monks, a lay follower should not engage in five types of business. Which five? Business in weapons, business in human beings, business in meat, business in intoxicants, and business in poison.
"These are the five types of business that a lay follower should not engage in."

FYI in this commentary on the Vinaya, on page 308, it says,

Raw flesh and blood are allowed at Mv.VI.10.2 only when one is possessed
by non-human beings. Thus, in more ordinary circumstances, one may not eat
raw fish or meat even if of an allowable kind. This would include such things as
steak tartare, sashimi, oysters on the half-shell, raw eggs, and caviar.
Furthermore, even cooked fish or meat of an allowable kind is unallowable if the
bhikkhu sees, hears, or suspects that the animal was killed specifically for the
purpose of feeding bhikkhus (Mv.VI.31.14)

So, apparently, according to this, oysters (and eggs and caviar too) are considered flesh or meat.
Whether you're vegetarian is slightly up to you. This article too (of unknown authority) says not to "steam live clams or eat live oysters" but explains why it's seen as relatively OK to buy meat under certain circumstances.
There was an argument between the Buddha and Devadata apparently, with the Buddha's not mandating vegetarianism because he didn't want the Sangha to be difficult for lay people to support.
FYI one of the criteria for the "no killing" precept is whether you're conscious that the being is alive and that you intend to kill them: killing someone by accident if you thought they were already dead, for example, wouldn't be breaking the precept. So, who knows, maybe it's partly up to you decide or to be aware of whether they count as "animals" or "meat" or "sentient".
I found this modern paper which claims that they're not especially sentient, but I doubt that's canonical.
And some people would have you know that even being a vegetable farmer or crop farmer presumably wouldn't prevent the deaths of worms and possibly field mice and so on.
Anyway, good luck with finding a solution.
And don't know any context to the Vanijja Sutta (it's in the Anguttara Nikaya as a list of five things). You'd think that if "Right Livelihood" were important enough to be in the Eightfold path then it would be better defined; but maybe it's better defined for monks than it is for laypeople; or maybe it's tangential to the main message, i.e. the Buddha's messages wasn't especially about right livelihood.
The book The Buddha's Teachings on Prosperity which is a bit of compendium of rules for lay people doesn't talk about "right livelihood" exactly but does say "don't destroy life". It claims that the Gihi Sutta (although I don't see this there) says that you should avoid trapping animals unless you're too sick or weak to farm.


Body scan guided meditation that covers only the upper body?

Just modify the instructions accordingly. A proper body scan just involves probing and examining the kinaesthetic response from every cell your body, not just the skin, but internal organs and everything in between. You don't have to start with the feet or the head, you can start wherever you feel like, can stay as long as you want. But the more you can pervade your awareness to every cell in the body, the better results you're going to get in your meditation practice. The longer you work at it, years and decades, if you're serious about your practice and dedicate several hours a day to it, energy channels will open up and it will feel like you can sense every cell in body, even all of them simultaneously.


Does an Arahant yawn? Or: What are the characteristics of the Noble Ones: Sotāpanna, Sakadāgāmi, Anāgāmi and Arahant?

What does the sutta's say about the characteristics of the Noble Ones? The Abhidhamma, for instance, tells me that a Sotāpanna can't break the 5 precepts anymore. This is one characteristic one could look for then.

It's from Sutta, not Abhidhamma. Sutta Pitaka Vol 10 : Sutta. Saṃ. Saḷa. pāṭaliyaSutta...

“Gāmaṇi, I know the destruction of living things, results for the destruction of living things, I know the method by which the destruction of living things after death lead to loss, to birth in hell.

...

“Here, Gāmaṇi, the noble disciple gives up and abstains from destroying the life of living things, gives up and abstains from taking the not given, gives up and abstains from sexual misbehavior, gives up and abstains from telling lies, gives up and abstains from slandering, gives up and abstains from rough talk, gives up and abstains from frivolous talk, giving up the coveting mind abstains from coveting, giving up the angry mind abstains from the defilement anger, giving up wrong view develops right view.

So, what does this all mean practically? Okay, a Sotāpanna doesn't break the precepts. What about a Sakadāgāmi? Does this elimination of grosser forms mean (s)he never has sex? Does an Arahant not yawn, because (s)he has eradicated sleepiness?

In short you can see this search result.
In detail, Sotapanna has the powerful craving in five strings and still able to angry because of those five strings, but he understood the dependent origination (right relativity of five aggregates) already, so he clearly realizes the result of all unwholesome formations. However, he can completely decide to cease only the craving in the actions which caused by wrong view, such as the five precepts because he still has the powerful craving in five strings.
Sakadagami has the weak craving in five strings and still able to angry because of those five strings. Sotapunna is just at the beginning to cease craving, but Sakadagami is at  more than half of the cessation way. It's similar to a fresh man and a senior because both of them still not graduate, but they are completely different from each other because of their experience in the university. Sakadagami is seasoned.
Anagami has no sexual feeling any more. He has no craving in any five strings. He still has only the sleepiness in meditation, the forgetfulness in meditation, the craving in being, the craving in not being, and the craving in the difference of own being and the others'.


What is exactly Avijja -- and how to uproot it?

Maybe you've heard of the old South Indian Monkey Trap (from this article):

  In Zen And The Art Of Motorcycle Maintenance, Robert Pirsig’s
  bonkers-but-brilliant philosophical novel that turns 40 this year, he
  describes “the old South Indian Monkey Trap”. ... The trap
  “consists of a hollowed-out coconut, chained to a stake. The coconut
  has some rice inside which can be grabbed through a small hole”. The
  monkey’s hand fits through the hole, but his clenched fist can’t fit
  back out. “The monkey is suddenly trapped.” But not by anything
  physical. He’s trapped by an idea, unable to see that a principle that
  served him well – “when you see rice, hold on tight!” – has become
  lethal.

The monkey needs to let go of the rice in order to free himself from his suffering. The way to end his suffering, is to end his craving for rice.

But in order to end his craving for rice, he must first understand how his hand is stuck inside the coconut. When the monkey overcomes his ignorance about how the trap works, he would let go of his craving for rice, and release his clenched fist. With this, he would be free from his suffering.

Also you can say that the monkey's suffering originated with his ignorance of the trap.

Knowing how the trap works, i.e. gaining insight and wisdom into the nature of reality, is the way to overcome ignorance.

(Illustration above: Paul Thurlby for the Guardian)


I think that the answer is 'yes, progressively'.

When you say "supermundane paths", this says,

  According to the Abhidhamma, 'supermundane path', or simply 'path' (magga), is a designation of the moment of entering into one of the 4 stages of holiness - Nibbāna being the object - produced by intuitional insight (vipassanā) into the impermanence, misery and impersonality of existence, flashing forth and forever transforming one's life and nature.

Therefore, 'supermundane path' means the same thing as Four stages of enlightenment.
In each of these stages, there's the corresponding abandoning of more and more of the various 'fetters'.
This link says that the five hindrances include the ten fetters, and there's a table that says at which supermundane stage each hindrance is eradicated.


If i may kindly correct the beginning sentence of your question, i.e. "In Buddhism, we believe in rebirth and karma."
We actually try to verify these things for ourselves by studying reality through insight meditation, thereby gaining insights into how reality functions. We practice to gain experiental knowledge instead of believing things to be in a certain way.
Through insight meditation one will come to see that phenomena arise dependent on causes and conditions. One sees that phenomena can spawn new phenomena.
Looking for a first cause is problematic. Why is that?
A first cause breaks causality. One can then ask "What caused the first cause? Or What caused the cause that caused the first cause? And so on ad infinitum".
This question of origin also belongs to The Four Imponderables, namely the 4th one "Speculation about [the origin, etc., of] the cosmos is an imponderable that is not to be speculated about".
The Buddha explained that is it not conducive to ones practice to think about these things. That is because one cannot understand it unless one is a Buddha. If one is not a Buddha thinking about them will only leave the mind agitated and distressed which will not be beneficial for ones practice.

"Therefore, o monks, do not brood over [any of these views] Such brooding, O monks, is senseless, has nothing to do with genuine pure conduct (s. ādibrahmacariyaka-sīla), does not lead to aversion, detachment, extinction, nor to peace, to full comprehension, enlightenment and Nibbāna."
-- SN 56: Saccasamyutta.