1) if 2 of a suite, bet as much as you think they will call, but at LEAST 3/4 of the pot (even all in can be a great play here)

if 3 of a suite, check/call to the river hoping that the board pairs... if it does, take everything they have with your FH.

2) It's probally +EV to call, but fairly often your going to be against AA... Depends on the player really.

3) sure, if your last to act and no one has bet, then try to steal... dont keep bluffing though.

4) I'd fold.. thats probally a weak play, but unless i have a good read i'd fold.