Hand 1 - my gut reaction is easy fold. But, this is top 2 pair. The only hand you can really be worried about is 44. So I like a call

Hand 2 - besides pre-flop, fine

Hand 3 - pop turn to $12

Hand 4 - yes, bet $6. makes it easier to play for stacks, turn fine

Hand 5 - does he typically c-bet? If you're going to donk it I think either pot it or bet 1/2 pot hoping he raises