Hand 1: A flush draw has good equity on the flop, none on the river. It is not a showdown hand and therefore money needs to get in the pot before showdown; the sooner the better. I like a raise to $25 and shoving (~pot)any turn. I chose these bet sizes because they give you the most F.E. on the turn, and allow a hand like A-J/A-10 to stay with you on the flop and surrender on the turn. Shoving only gets called by A-K/sets and you lose a lot of semibluffing value by not allowing weaker hands to call the flop and fold the turn.

Hand 2: looks like Villain has Q-J/set. I would fold this. call flop raise turn is a standard donk set line, and against an unknown i won't assume that i am being bluffed.

Hand 3: fold/shove PF. I would fold. While villain is loose, he isn't exceptionally aggressive and a 4bet facing 2 raises is very strong unless either/both you and the other opponent have been ridiculously aggressive.

Hand 4: I mostly want to talk about your flop bet:

Villain may c/r bluff, but at 100NL in a RR pot where you were the aggressor i doubt villain is going to get fancy. I personally see these bets as suck bets and so i prefer to bet an amount close to pot even when i flop top set. You are unlikely to get action either way so you might as well put more money in the pot.

Regardless you were highly unlikely to lose the pot, and even as played there is no way to fold this hand.