well at least she doesn't look like a lesbian, like the comics.
I'm going to say no to that. It's reaching WAY too much to make sense. What's more likely the case is that Stan Lee as a person is exempt from whatever franchise deals are in place, so he can play whoever he wants in any movie.
I suspect that as far as the movie rights are concerned the situation with the Watchers is much like that with the skrulls. Fox has the rights to some if not all of the specific Watchers that existed at the time they they acquired the rights to the FF but the Watchers as a race of beings can be used by Disney/Marvel as well. As long as they don't name drop something like Uatu in association with Stan Lee in one of their movies it's probably fine for them to depict him as a Watcher.
Except that doesn't apply to Ego, does it? In the movie, they specifically referred to him as Ego the Living Planet. He is 100% owned by Fox if it's movies. Hopefully this harkens to Fox and Disney working together on other characters.
No Marvel worked a deal with Fox for the rights to Ego involving Negasonic Teenage Warhead in Deadpool.
...which means that Fox may be more open to working out deals from now on.
This only furthers my point.
When Spiderman comes out and does $1.2B, I bet they'll be open further.
It's certainly possible. Though I think Fox probably looked at Ego and figured they would have little use for such an odd, niche character anytime soon, so they were much more willing to deal the rights away.
Still, the relationship between Fox and Marvel is pretty chilly. Marvel has gone out of it's way on the comic book and merchandising end to marginalize the properties that Fox has the movie rights to and don't think that Fox hasn't noticed.