What to expect / general approach to "donk pot bets" ?

Hand 1 -
Hero (100bb) BU - AsJc - open raises 2.6bb
BB (60bb) - calls

Flop - Ah8h3h (pot 5.8bb)
BB checks - Hero bets 2.7bb - BB calls

Turn - brick (pot 11 bb)
BB checks - Hero bets 6.5bb - BB calls

River - 8c (pot 24 bb)
BB bets 22bb ...
(He was short, bet half of his stack)

Hero (in this hand I fold), but which hands do I need to call ?
(AQ call, Ace with a J or K of hearths... ) And which hands to raise ?

Hand 2 -
SB (100bb) - raises 3bb
Hero BB (100bb) - AhTh - 3bets 10bb

Flop - Tc4h9c (pot 20bb)
SB bets 20bb
Hero ... ?

In this hand, if I call the flop, probably villains donks / shoves the turn.
What would be the best approach ? Fold ? Raise all in on flop ?

Hand 3 -
HJ (100bb) raises 3bb
Hero (100b) on CO 3bets 9bb with KhJh

Flop - 6s3cJd (18.5bb)
HJ bet 9bb -> Hero raises 31bb

Questions:
- Would you raise? How much?
- What if villain shoves flop?

I raised with the intention to shove/call any turn, so it was a no way back flop decision to me. Was it correct ?