You're missing Kvyat who's likely to be gone. He'll be replaced by Tsunoda if he finishes in the top 4 of F2, which would give him the superlicence points he needs. He's in Marko's program and backed by Honda so hard to see them not going with him. If he doesn't get the points then Liam Lawson might have a shot to make it straight from F3.
If Mick goes to Alfa Romeo then I'm guessing they'll try to keep Kimi just to have a veteran driver around. It would have made sense for them to be agressively scrambling for Vettel's replacement but now that Ferrari is set on their drivers there's no real urgency for the 2nd team to be in yolo mode.
Mick is good and it's a little harsh to claim an extra year of F2 being "far too long", he's consistent and seems to be absolutely elite at starts while qualis definitely need some work. He's 100% to underdeliver the insane expectations that people will put on him so you're kinda right. The current F2 band is insanely good and there's like 5+ drivers who all deserve a shot in F1 so it's extremely competitive.
Haas is considering among
close to 10 drivers. They seem like a bunch of wankers who don't really have a clue. Maybe something like one of Hülk/Perez with a Ferrari affiliated rookie, most likely between Illot/Shwartzman.
Latifi is already under contract for 2021.
Bringing Alonso back is crazy, not sure what they're paying him or what he might be bringing in but hard to see everyone involved not regretting this move.