Hand 1: Agree with Andy, you need to 3bet push that flop considering stack sizes.
Hand 2: The problem of not 3betting is that you're letting opp draw for free if re-raised with a flush draw. A part from the flush, I could see also hands like 99+ small re-raising that flop (opp depended of course). As played, I would bet $13 on the turn and fold to push/raise.
Hand 3: nh
Hand 4: bet flop and fold turn if he bets strong.