[xJMPx]

Hand 1: BB has less than 5BBs, you can push any two here.

Hand 2: Standard

Hand 3: I’d probably raise this if I was going to play it.

BB could be holding any two in an unraised pot. I would say his check raise is showing real strength, so I would fold to his raise.

Edit: I just took a look at your stack size in hand 3, I would fold preflop. I don't like anything less than all-in with 10BBs here, and I wouldn't want to push this just yet.