Are Saprolings still Tokens after playing Life and Limb?
Yes, they are still tokens.
First of all, Token is not a card type:

205.2a The card types are artifact, conspiracy, creature, enchantment, instant, land, phenomenon, plane, planeswalker, scheme, sorcery, tribal, and vanguard.

A token is any object on the battlefield that is not represented by a card. Note that a token is still a token even if you use an MtG card to represent it.

110.5. Some effects put tokens onto the battlefield. A token is a marker used to represent any permanent that isn’t represented by a card.
110.5e A token is subject to anything that affects permanents in general or that affects the token’s card type or subtype. A token isn’t a card (even if represented by a card that has a Magic back or that came from a Magic booster pack).

No effect can ever turn a token into a non-token or vice versa. All Life and Limb does is affect a permanent's card type which, as shown, has nothing to do with the object being a token or not.
That answers your questions 1 and 2. Tokens remain tokens under all circumstances and the same rules apply to them with or without Life and Limb.
Question 3 is only tangentially related to Life and Limb and is answered here:
What is Summoning Sickness