I plan on integrating NEAR wallet login in my game, but it’s currently not possible to login to NEAR from itch.io. I wonder if it’s allowed to host the game on a different platform (e.g. 4everland, or Netlify) in addition to itch.io?

Yes, feel free to host game elsewhere and post a link.

Check out this thread as well https://itch.io/jam/human-game-jam/topic/1924180/make-sure-to-join-our-discord

Note that you also don't have to implement NEAR login for the scope of this jam – main idea is just to demonstrate game idea. We'll be giving extra grants after game jam for actual integration with NEAR and production launch.