I have seen a few of these things... mostly silly questions and obvious "left it for the next movie" (or just leaving it for fans to speculate and build hype)
I keep noticing bits of expanded universe in many bits of speculation... I think some people are having trouble separating the two
BB-8: Well, if you understand the physics behind how BB-8 works (remember, that is a working droid prop) it is simple to change the counter weight to "lean" against the higher step allowing him to move down stairs. As for up the stairs... grappling hooks... we saw him use them.
Rey: I see some validity to the Mary-Sue comments but the thing is that Finn and Poe are also Mary-Sue's... as are JJ's Star Trek crew... I agree it is crap writing, and a lot of it could be fixed by omitting or altering dialog like "He's the Best pilot EVAR!!!!" It has nothing to do with feminism and the fact that you point the finger there is sad.
As to the hug... maybe Leia knows or suspects something that you do not? Also maybe it was just a "Some one you loved just died and you needed a hug" type thing? I suspect either works.
Snoke would be the worst name ever.... if it weren't for Jar Jar Binks, Sy Snoodles and Boba Fett (and more) Seriously, what is with dumb names and Star Wars?
And remember, at least it wasn't Episode 1...