1) Opponent 18%/15%
http://www.pokerhand.org/?1979790

2) Opponent is a serial caller
http://www.pokerhand.org/?1979811

3) Opponent is tight so far
http://www.pokerhand.org/?1979824

4+5) 2 hands like this:
I hold AK suited and AQ suited, and flop both come up with 2 of my suits after pre-flop raises of 3 and 4*BB. Both times both opponents called my Pot Bet and the turn missed my flush. Neither board was paired but there was a straight possibility on one hand. Should I fire again - with how much ?

1: The preflop call is a bit marginal, however postflop is super standard.

2: I generally raise preflop, as played just call with the great odds he gives you, serial callers pay off when you hit, no need to play it fast

3: Fold preflop, as played just call the flop and see what the turn brings - the flush draw out there basically negates two of your outs.

4+5) Check and take your free card

Hand 2) If you are going to raise the flop then just going ahead and push in because villain is so short. Playing it slow is fine too since you ahve position.

Hand 3) I don't mind the raise but I think you fold now.

Hand 1 is super standard, you are deep enough this is a super easy call. The flop writes itself with your opponents cards.

Hand 2, super standard but I would have pushed on the flop, but villain being short I don't think it really matters.

Hand 3, fold PF