Very small birds sometimes like to hang around or even nest near large raptors. The small birds are too small to be worth eating for the big predators, but they keep smaller predators that might be a danger at bay. I’ve seen this specifically with hummingbirds.
Looks like forced perspective. I think the hawk isn't looking at the little bird, but from our angle it looks like they're face to face, so we assume they are much closer than they are.
That’s definitely not a sharp-shinned hawk. Looks like a buteo of some sort but I’m not the best at hawk ID. Maybe a red-tail. They can have so many different color morphs I am never sure though.
Sharp-shinned hawk is much smaller and has different coloration.
When watching eagle nest cams, I've seen little birds and mammals hanging around eagle nests and scooping up scraps of leftover prey. I think in many cases a large raptor isn't going to go chasing around a little birds when they've already caught something bigger and the little birds play clean up crew and take away scraps that would be too small for the larger birds. Not sure if that's the case here but it's a cool little cooperative situation to notice. You'll also see little birds nesting under osprey nests, probably for the same reason.