Villian seems loose, but pushes his good hands hard post flop, I've seen several hands indicating so.

I have about 270 in my stack (CO) and villian has about 600. (MP1)
I have AhQh
UTG+1 raises to 10 MP1 calls MP3 calls CO (me) calls, blinds fold.

Flop is AcKs5c.

UTG+1 bets 25 MP1 raises to 50, MP3 folds, my action?

Fold... Don't call off $10 in this game and then go nuts when you hit TP... Maybe if you all had $500 in front you could make a move, but any raise is putting you allin, and you're more than likely behind..

Reraise preflop.

Fold. I either flat call preflop, or reraise depending on my read. If they're a loose raiser and I can easily outplay them, then I call. If they're tougher, then I raise to gain momentum to take it down on the flop.

I think the best line would be to make a big re-raise preflop. UTG+1 just miniraised so most likely has some crap like Axs, a medium/small pair or some face cards. The others showed weakness by just calling. If UTG+1 has a big hand you want to find out early, and if he hasn't you should be able to either pick up the pot right now or limit the field to one or two players. Pop it to 60, then make a CB on any decent flop (like the one you got) but be prepared to slow down.

Since you're suited AND have position I don't hate the preflop call with two callers infront of you, but this is not the flop you're looking for in a multiway pot. It will probably cost you your stack to find out if your top pair is good, and against two opponents that show some aggression I don't like your chances enough. You could definetely be ahead, but I think you're better off fining another spot, as played I'd fold the turn.

Yeah against people who will donk off their stack with TP you should play much looser preflop but tighter post flop. Hell, against bad players in general you should loosen up... in fact, loosening up is pretty much the answer to anything except preflop LAGs.