I think people can sometimes mask themselves without being very aware of it. Sometimes I've caught myself acting in a way that seems designed to make me look normal, though I can't recall any examples clearly.
I remember telling somebody I was on the spectrum, and their immediate response was "crikey, you hide it well!" I was surprised because I'd always thought I was just being myself with a bit of gloss here and there.
I like no.9 on your list - "Social overtures were mainly related to own interests." I find it almost impossible to make social overtures about anything else but my own interest. All this "how's your wife and kids?" stuff is just a theory to me, I can never remember to do it and even when I do remember, I can barely muster the enthusiasm to bother with it, and I'd feel rather fake if I did bother. I rely heavily on others to volunteer stuff about their own lives, and on overlapping interests to keep us from boring each other to death. I once read that without common interest and purpose, people can't relate to each other and will soon fight or separate. No wonder I'm picky about who I hang out with, and no wonder so few people beat a path to my door.