For your first Point
I know people will say its different but Panda goes down for two events now
They sell day tickets and 2 PM ticket....you want the Mummy you can go then
Disneyland has rethemes for Space and most guests enjoy that, normally the line for Ghost Galaxy, Rockin Space Mountain, Hyper Space mountain etc have longer lines then the normal version.
Second on Money that one could be much harder, but could also be a dual deal, like for example Stranger things like you pay a rate or a higher rate so they can have both a house or a rethemed ride. Not saying every company will want this but I'm sure they can find someone who it makes sense to or even just use a Universal IP on the cheap
If it doesn't happen all good, but saying The Mummy is a perfect coaster for a Retheme, it has screens in the Q for the Story, the ride is mostly dark and you could set up area's to project on like they do with Hype Space Mountain, the Bug part is screens so that easy to redo and the last room is also easy to redo. I am not saying it will happen but it just makes sense as something they could use
I'd also be happy to see Despicable me be used rethemeing at Fan fest or HHN and I would say Simpsons but its times so limited I doubt they want to use it for anything else but would be game if they do