Hand 1: Hmm the turn isn't really a scare card for villain. It's a pretty easy float though, so I don't mind the 2nd barrel. It works often imo, so this could just be results oriented. A turn c/r is sweet too.

Hand 2: Because you're OOP I'd raise to at least 6 preflop, you're pretty much giving him the right price to sethunt or call with SC's.
There certainly is merit in pushing the flop as this is 1010/JJ often. You cannot fold out hero having a 7 or 44, but it's pretty much opponent specific to either push, call or fold the flop. As played, you have to fold turn because of his betsize.

Hand 3: You at least have to call this flop. Betting isn't bad and I like a c/r even more. It's very likely your opponent missed this flop so you're more often then not ahead here with just the 3's. Combined with the gutshot you're good here.