[fingersmith]

So obviously you have to adjust a villain's range for doing this based on their frequency of doing it. The problem with this, when multitabling, is that if lots of different villains do it, you (or at least I) start to feel like I'm getting played back at super light. But in reality, they could all have legit hands.

Given this, unless I think a guy's range is really wide for doing this, my standard plays are based largely on position. So
hand 1: fold, sadly
hand 2: if this is his first time check raising, fold. with a read that he does this a lot probably call once because of his high vpip. he could have a lot that he thinks is good. often they check the turn and your hand ends up being good. fold is totally fine though.
hand 3: same as above, except this is closer to an always call for me. checking the flop behind is a great option here as you suggested. People seem to think this is a good idea with any pocket pair for some reason.

if a particular guy is going crazy with check/minraises, obvious lines include:
- 3betting the flop with air + outs (and some good hands)
- checking behind marginal hands and getting value on the turn and river
- calling the minraise and basically calling down depending on bet size.

If we are OOP this is a lot harder to deal with, and we're more likely to have to 3bet the flop instead of calling down, or c/r the turn with good hands--but most of all, fold more often