2 streets seems reasonable. I would probably go turn, the river gets very dynamic.

Checking back river is entirely reasonable, very difficult to get called by worse. Pretty much only QT or Q9. On turn we can probably bet, he can easily have hearts or a 5 with a draw, and I just don't think he's going to bluff much on most rivers. That said, I can't imagine checking turn is unprofitable even if it may be marginally less profitable.