I always read that long reaction shot from Han, after Rey's line about all the green in the galaxy, was him mulling over offering her a job, which he does in the next scene. She's flipping out over some trees and he's thinking about how little she's seen of what's really out there. He offers her a job in part because he could use her, and in part because she basically needs to get out.
I mean, I don't know how ELSE to take that moment. It's blatantly obvious that this is the intention.
Like I've said before, I truly think that if Rey were a Solo or even Skywalker that we'd have found out in VII. The storytellers aren't stupid enough to delay what would be such an obvious answer for this long.
It'd be like waiting two years just to have basic suspicions confirmed. If they made something like that into some huge twist it would fall so flat and nobody would be surprised. It would backfire hard unless there's a lot more to it.
So it's none of the above. I obviously don't know what happens, but it would be fucking NUTS for them to pretend like something along those lines would surprise anyone. If she's related to a known lineage, it will be distant or something few people have guessed or suspected.
My feeling is that she's... Rey. Somebody. She has her own family, she's not related to Luke or Han. And again if she is, there's going to be some really interesting curve to it or details nobody has guessed.