Hand 1 - yah this is good. Think the sizing is fine too, though maybe a tad smaller on the turn if he's the type to get scared off by flushes.

Hand 2 - I think folding river is fine/close. There's not much you beat anyhow and he could be betting so small with two pair, and worried about the straight/flush.

Hand 3 - Yah this is good. I wouldn't bet the river, your hand could be good and he could be trying to bluff catch vs the exact type of hand you have. He could also be hoping you bet with Qx so that he can c/r a flush/boat.