[Jimbobobb]

Hand 1: I'd check/fold the flop honestly. Given your flop bet I'd bet out again on the turn, and fold to a reraise. With the board double pairing on the river, in a .5/1 game no ace is folding, and I'm surprised MP1 didn't bet.

Hand 2: 3-bet that flop. If MP2 caps it, slow down. Why 3-bet the river? UTG just calling all the way scares me, and MP2 most likely has you beat.
Just looked at the outcome - I think UTG played this horribly - if you two had been raising like I think you should have, you might have given MP2 a tough 2-call on the flop (and an even tougher one on the turn), and forced him out.

Hand 3: 3-bet pre-flop. Leading out the flop is good. I would have led the turn as well, but check-raising after MP's bet I think would have been the best play - make the 2 between you call 2, and give you a better idea of where you stand. Bottom pair pairing shouldn't scare you that much.

Hand 4: I'd say raise the flop. I don't like the calling all the way.