1 - In general sizing is too small on turn, river would be too thin imo.

2 - Think river is a call. He doesn't have KK, QQ, TT because he'd fire the flop because it's so wet. He doesn't have AJ here very often seems a bit wide vs an UTG open so the only realistic hands he could have that beats you is AA. All just seems a little off imo.

3 - Folding seems fine I think.

4 - You're probably fine doing this against an unknown imo.