Are these studs likely loadbearing? Can I move one?

Safe answer seems to be that 1 and 2 studs support a landing that supports both upper and lower staircases, so I would leave them there. I can't see enough of the whole structure to suggest something else.

#1 There was suppost to be 5/8 fire rock under those stairs.
#2 Just make a door way in the side wall.

I really don't see a problem removing #1 or #2 cripple, not both though. You really need to install a header at the top of your stairs there is just not enough support for the three stringers at the top.

are those stringers installed correctly ? looks to me like they are not.

I hear ya Big Jim & Fix'n it .......

guess they stay up because they're used to being there, looks like the stairs could use a little TLC.

a proper header above #1 & #2 supported by the studs on the side would work. I'd certainly take care of the issue at the top of the stringers as you currently have little support