1). You can't fold an overpair here on the flop. However there are a lot of scary turns that you can fold on if he bets again. If the turn is a blank and villain makes a reasonably sized bet you should go all in.

If he was playing passively over a large sample then i think you could fold to a check/raise.

2). I might raise to 17-18 instead so the turn bet to put villain AI isn't quite so large. Otherwise the hand is played well.

3). I would not float this flop. The flop is likely to have either given him a pair or a better draw than the one you are floating with. Particulary if he is playing aggressively he is going to be betting at a lot of scary turn/rivers that will force you to fold later in the hand. River value bet is good.