Ideas on Rafe's relationships with the rest of the cast:
Avery- I can see Rafe really liking when Avery shows her strength and in a way probably really looks up to her for that strength. Since he's naturally really calm and collected, I could possibly see him attempting to help when she has a panic attack? Either way, I could definitely see them as friends who probably met through one of the others.
Max- Max and Rafe's personalities would probably clash somewhat with Max being more reserved and Rafe being more than a little too detached from reality. I don't think they'd exactly be enemies, but I could see their personalities sometimes grating on each other but still being friends to begin with on a fundamental level, I think?
Alexei- You mentioned that maybe he met the group through working as IT at someone's job for a bit? Maybe he worked at the law firm Rafe works at as IT and Rafe invited him out for a few drinks and they hit it off? Just a thought.
Johanna- I agree that Rafe and Johanna probably hang as drinking buddies every once in a while. I also think Rafe trying to help with Johanna's divorce or even tried to find connections to get her a good lawyer during it might be an interesting dynamic.
Matt- Good friends. I'm definitely game for them meeting at a bar and originally disliking each other but now are really close. I could see Rafe really enjoying listening to Matt talk about his interests and maybe even getting into a couple of them just to see why Matt likes them so much. Possibly roommates if you think that'd work?
Anastasia- I could see Rafe and Anastasia's friendship to be incredibly back and forth. Since they're both sharp-tongued (although I'm betting Anastasia's way better at remarks than Rafe is) they probably snark at each other every once in a while, but I could also see Rafe glad that Anastasia takes up the mediator role in the group. Maybe somewhere between acquaintance and friends?
Luci- I could see Rafe really supporting Luci's party hardy lifestyle, thinking that no one should make themselves constantly into all-work, no play. He'd probably be totally confused about anything she says about engineering since he's really book dumb which could cause for some funny interactions. Maybe met during college?
Marcie- I could see them in a slightly bickering but friendly dynamic? Like on one hand, I could see Rafe pointing out the whole "Why are you a butcher but you never eat meat??" situation often, but at the same time often inviting her out to social drinking in hopes that she would hit it off with a girl there (or find an casting director, even though Rafe's probably too dim to realize that's a bad place to look).
Spencer- Rafe would be absolutely in love with Pepper and would be constantly trying to find excuses to play with her. They both came from middle class/lower middle class, so I could see them both understanding the value of the dollar and kinda bonding over that. They'd probably be the two working extremely hard to pay Max's loan back?