Hand 1 -
he has enough odds on the flop considering he has a gutshot, a backdoor 2ndnut flush, and the possibility that hitting a king (or a ten if he is lucky) could win the hand for him.

Hand 2:
This really depends on the MP at this point. If he is moderately okay, he would know that he doesnt have odds to call the turn with just a pair unless he intended to go to showdown. I dont know what sorts of hands he is cold calling with though. Once you have a range for his cold calling hands and whether or not he peels overs poorly (ie calling flop and turn with JT or QJ tihnking you missed) , whether to bet here or not become more clear.

hand 3:
You probably want to check raise the flop and lead turn. If he 3bets and I know he can raise for a freecard (or a chance to fold you) with overs a lot, I dont mind calling his 3bet and then donking the turn. But if you dont know if he raises with overs or not, you probably should just call down after the 3 bet.

hand 4:
I fold the flop. 2 suits on a semi-coordinated board - you could hit a pair and still lose. Also, button still has to act, and depending on how he plays, his cold call may represent strength enough to say you are behind.

hand5:
How this plays out depends on what he cold calls with and how much he peels if he feels you havent hit, despite whether he has or not. I would probably check-call the river, depending on how loose and how donkey he is. I might check-fold too sometimes.