1. Were you an INTP only child or did you have one or more siblings?
One brother a few years older than me. He currently lives nearby (about 15min drive) although by next year I may be moving away. I'd tentatively type him as some sort of ExFP, if it matters at all.
2. On a scale of 1 to 10 (least to most), how well do you superficially connect to other people? Meaning, ability to shoot the breeze, hang out, etc. Nothing deep.
I'd say somewhere between a 5-7. I'm generally able to hold a basic conversation but I contribute much less than most people would. A usual conversation is someone tells me something mildly amusing (but not THAT funny) so I give them a little chuckle and nod and say "yeah" and all that and if I see that the other person expects me to say something else I'll try to come up with a question about them or whatever they're talking to me about in order to give them an excuse to continue talking.
3. On a scale of 1 to 10 (least to most), how much do you feel deeply connected to other people?
4ish. It's not so black and white, though, with a set number and it depends a lot on who it is. Most people I know would be closer to a 1 simply because I don't know/like/trust them enough to share my deeper thoughts with. Whereas I have a few friends that I just get along with on that deeper level really well and all that jazz.
I think having my brother in my life definitely did affect me in many ways. Where my parents didn't or couldn't teach me about the world, my brother would be pretty decent at doing it. He brought friends over a lot and I was able to watch how they interacted and learn how to make friends and stuff, among other ways he helped me figure out how to be all social. Granted, we never really were all that close (being four years apart meant we never went to the same school at precisely the same time, and we're just generally different people) and I definitely don't think he's trustworthy enough to talk about "deep" things with, but he's a fun and cool guy and I think he'd genuinely try to help me if I ever needed him to.
I'd say that he's always been more of a role model for me than, say, my parents. It was just easier to look up to someone from my generation than a couple old people. He was always social and had lots of friends and went to parties and was a pretty smart guy, and I wanted to be like him. Whenever he had friends over I'd follow them around and try to act like "one of the big boys" and like I could fit in with his group.
That said, since about sophomore year of high school, I slowly felt less like that. It was around that time where I had an unprecedented string of anxiety attacks unlike any I'd had before (I've actually dealt with free-floating anxiety my whole life, but this was just an awful month). These panic attacks kind of opened my eyes to the fact that I couldn't really be the social butterfly like my brother, as the anxiety was almost entirely caused by social factors. After this I came to value my introversion much more and no longer wished to be like him.
So, yeah. Kind of a long answer. Hope I helped.