yeah only the insiders know the real rights deals with the Hulk and Namor, however I believe they can use them as a cast member of a larger picture. There might be a limit of screen time to block use in a feature film. Perhaps staring in no more than 1/3 of run time. Namor has the mutant issue as well. Maybe he can only be used as a non mutant right now until the deal closes. Then there is the distribution deal.
The Fantastic Four really were the explorers of the Marvel universe. During the Kirby - Lee era we discovered the Skrulls, Watchers, Kree, the Silver Surfer and Galactus out in the cosmos. We also went to places like Latveria, Subterania, Atlantis, Waconda, Attillian, and the Negative Zone of the 616 universe. So many great places and characters that have laid dormant while endless terrible movies have been produced never getting further than the Galactus, origin, or Doom stories were told, and those were changed so badly hey have damaged the franchise.
I can only hope that they finally do this franchise justice and fix how badly Fox treated this property. There are so many great stories waiting to be told that Disney plus really is the best place to introduce this team to the Marvel movie universe.
I could easily breakdown 7-8 movies based on the first 104 issues of the Lee - Kirby run. Even at Harry Potters movie pace that would take 10-13 years to produce.
Disney should make sure that all actors contracts allow for the Silver screen, Disney Plus and the small screen going forward.