I think they are hiding some cast members. Notice no Hulk actors, no Spider-people, and no god tier characters.
Yes, clearly they are. They've been very hit or miss in their efforts to set up the post Endgame MCU (a lot of it due to behind the scenes industry & social political issues) they need something to generate excitement and engagement. Nothing better than throwing out all of the live action Marvel characters that Marvel/Disney now have creative control of in another event style movie or two. Also sets up a new MCU status quo if they are doing their take on Secret Wars/God Emperor Doom story.
Yeah, doing secret wars without Spider-Man doesn't make sense. I also think the X-Men cast are just going to be cameos or CGI de-aged and not full-fledged part of the cast, most of those actors have aged way past the way they looked in the Fox X-Men movies. I'm personally hoping we get to see other cameos like Ghost Rider, Daredevil, Moon Knight, Luke Cage and Jessica Jones, Cloak and Dagger, and Jeff The Land Shark. I also really hope they DON'T put Deadpool in it (At least not the Ryan Reynolds version.)
The actors that have been revealed so far will either be central characters or extended cameos ala the Illuminati in Multiverse of Madness or the Lost Variants in Deadpool & Wolverine IMO. They'll throw in Daredevil and all the rest as legit cameos just to establish that they exist so going forward they can show up in the MCU (especially if different actors are cast for some of the characters.) I don't think (& also hope) Deadpool isn't a central character. He'll definitely show up in a cameo role, but I can't see them keeping him around if they have other central characters playing comic relief (looking at Paul Rudd's Antman & David Harbor's Red Guardian).