Awesome questions, thank you!! My thinking was to have the final contributors post the games to itch and add the other contributors as admins to the game, but as Luke pointed out, I think it's likely that many people will be posting their .txts. I'll be making all .txt or other text files available to everyone after the jam is over (and as final submissions come in), so individual collaborators can post their contributions or final submissions to their own itch pages if they'd like (and format/edit/change to their liking).
I'm nervous to suggest any recommended pricing - I think I'd prefer to have collaborators discuss amongst themselves. The .txts will be made available to readers for free so that they can judge them, though!