Hand 1: This is kind of read dependent, but I lead the flop here for 2-3k. There's a decent chance that someone here has a pair or a draw and will call/raise. If you do go for the c/r, you can raise to 7-9k or so instead of pushing. This is also read dependent, as some villains view pushes as bluffs, others will tend to push over a raise here, and others will call the raise here with a pretty wide range.

Hand 2 is fine.

Hand 3 I raise more preflop because I think I have much more fold equity raising to 5k than I do raising to 4k as many people will default call a minraise on the BB. I play the rest of the hand like you did.