The only things definite should be Spider-Man and Avengers, and considering that they are presumably using Bugs Land and the Expansion pad around Cars Land and Guardians, it can work out more-so than replacing the Hyperion.
The only way I can see it, is if they do a stunt show inside of there similar to what Paris is doing though, but I don't think we are seeing that for a long while, considering Frozen.
Honestly, and this is my opinion; have Mickey and Minnie's Runaway Railway take over a portion of the Hollywoodland, give the Sunset Showcase and portions around that if it's not touched cosmetic theming, and change up the Hyperion facade to be more classical looking and more akin to the 1930s/1940s.
Then you can theme Marvel Land presumably off of a West Coast Avengers HQ (in reference to West Coast Avengers), explain that Spider-Man/Peter Parker is touring around the area, and have the Avengers attraction mainly take place in Urban LA.
I could see that, and it could even open the door to an Iron Man attraction if they save space for an additional Marvel expansion.
There are plenty of ways they can do Marvel in a California theme, but it has to be done right, and not just slopped around as a mishmash. It's what I fear most about this project, and that I am praying that I am amazed by what I see.