I agree, no complaints here.
Eyup.
If they have an elevated endurance against pain, could be considered a limited resistance, but normally resistance to pain is limited to people that have specifically dampened or totally removed sensations of pain (for example, the protagonist of Kick Ass). Without elaboration, I'd agree with removal.
The feat seems to imply he didn't actually do it and was unsure of whether he could, he only seemed confident in opening it a little. So I'd agree with your interpretation more than scaling him to the destruction of the door.
Correct, yes.
Ditto.
That thread didn't receive a single staff vote as far as I can tell. It wasn't accepted, although it may have been erroneously applied.
Yeah, no idea why you'd give Class 1 for that. Our own page awards them Class 1 only for a running charge, just grappling with them normally can be done arguably with Regular Human levels of lifting strength.