So it sounds like the Kamen Rider Ex-Aid Final Stage show features a few exclusive things. That happens sometimes, and I like when it does happen.
The big one, which is the only one I could find a photo of, is apparently being called Gamedeus Muteki by fans - I don’t know if that’s an official name but I would assume it’s at least providing the context of the form’s appearance. Which means it probably has nothing to do with Genm.
I also saw some mention of “Nico Snipe” - a Twitter user made some edited photos to represent these, and Nico Snipe is just Snipe with a pink cloak instead of yellow, if those edits aren’t just guesstimations.
Oh and Double Cheeseburgermon was the last thing namedropped. Delicious.