Being under contract does not mean you tell the public about said project. That's simply a courtesy Marvel offers. Especially them because they can keep said secrets about involvement quite well.
Well. I meant like the way, if a mentioning got squeezed in one way or another, due to the consequences from Doctor Strange in the Multiverse of Madness where single character survived the destruction of the Gifted Universe.
Honestly, after such a event, then there is no point of caring about which of the characters managed to survive.
Don't see how. Their journeys aren't really continuing. Plus Marvel isn't like DC in doing Crisis events that destroy their alternate Earths. Sure there are some that implode, but mostly they just stay doing their own thing for the most part aside from the occasional multiverse teamup or tragic death of one character from said Earth.
Even the ones that die are ones we knew wouldn't last like the Marvel/DC worlds. Things that couldn't possibly continue in the first place.
So many cameos of other material even within the MCU's own Earth made it into the movie that wasn't needed for the plot. Having an epic fan service opportunity is just missing it. It's not a good thing.