I would think that Nick Fury is basically a guarantee, unless that Far From Home credit scene is expected to setup something else.
She-Hulk? Maybe, since the MCU is on a woke path. Just cram all the girls together amirite?
Professor Hulk should probably just retire with that useless arm. He doesn't wanna fight, obviously.
They need to actually develop Captain Marvel into a likeable character. Any sort of ensemble for her sequel will basically be Marvel admitting that she can't carry her own film, and detract from trying to make her into something more.