A5s muliway

I wouldnt necessarily raise the flop, because we are 4way and even the fish will probably realize that you have an ace and our kicker is poor. I would call the mindonk on the flop and see what happens. If reg raises, we are beat. If he doesnt, I would bet the turn for value against the fish.

I think CO:s range is very strong when he calls your raise on the flop. I wouldnt even consider trying to make him fold. Regs usually even fold AJ preflop against UTG. If he bets small, I might check/call and try to hit a straight, but it has to be pretty small bet. BTW im a noob who also plays at these stakes so dont take this as a truth but as an opinion from another nl20 player.

I think we could also fold this preflop. A9s-A2s are probably questionable open raises from the UTG. As played, I wouldn't raise the flop. As played, I would check/fold the turn and river. Given all the action, I don't see better hands folding nor worse hands calling.

Otf you get a good opportunity to get down the pot. Ott I would play x/c with double gutshot acc. to the pot odds.

I would not open this hand from this position. You cannot defend it properly vs aggression.
Turn is a x/call, you still have outs, you have equity.