2-barrel as caller

I would bet lighter OTF. No need to bet that strong if faced with check from preflop aggressor. Dont need to worry about FD I think, he most likely would have continued aggression.

It's close decision OTT, he played that really weird tho, take into account he's stack is relatively short, we can consider him weak player, we may see him calling with worse hands and oddly played FD so I would bet 1/2 psb, if he's got like set or TP we will propably be raised and it makes our decision really easy.

As Berezovaya mentioned smaller betsize OTF - when villain check as a PFA he usually have weak range so we can have cheap bluff but also we usually need to bet smaller to gain some value.

OTT - not sure but I think bet should be OK - he can still call with worse (draws) and fold some better hands

Agree with the smaller bet on flop. With the higher card on turn bet/f seems reasonable.

What if I bet turn and villain calls? Is there any reason to bluff river in this case?

If he calls with A and K on board do you think it is good to bluff river. Do you beat the missed draws?

If he call turn, R is x/b I think - we win against busted draws and our foldequity vs better hands is probably not the best. However, with good read to the opponent bet R can be OK but x/b should be standard without reads.

Exactly. We beat the missed draws and nothing better is folding.

don't bluff fish on the river - we've taken two stabs, thats enough vs a fish imo