1: Trust your read and it should be an OK play. You say he steals a lot of pots, but does he value bet them as well (is his range merged?)? This flop hits a lot of ranges in different ways and we are really feeding off FE as opposed to actual equity so we need him to fold quite often. That's really all I can say. If his folding range is huge then go for it. You'll get a better feel as you keep playing.

2: Yeah if the shortstacker sucks then I like it. It's a risky play with so many callers but you don't want to do this much with nitty shortstackers.

3: Same deal with barely any equity if called.

I'd assume all these are pretty marginal. I'm kind of out of it right now so I didn't get too in depth but the gist is that if you can't put him on a very narrow range of cards that WILL fold often you are going to need some actual hand equity.