What is "Anapanasati" day which is coming on this November 14?
It's the anniversary of Buddha delivering the Anapanasati Sutta (Sutra on the Mindfulness of Breathing), an important Sutra about meditation

Reference: https://en.wikipedia.org/wiki/Uposatha#Special_uposatha_days

(Sorry but I don't know enough to answer the other questions you asked, but I hope this answer and reference helps to some extent)