Given what we know of costs for Pandora, SWL, and TSL, I'm thinking Futureworld alone needs well over 1 billion. While FEA cost somewhere in the 100-200 million for an overlay and line redo, there isn't much in FW that can suffice with that little work. That means you are looking close to 250-500 million per ride. If you think about Imagination, complete gut and rebuild for both ride and movie, that's got to be in the upper part of the range. UoE is a full re-construction judging from the permits, so that is mid to upper part of the range, Innoventions needs to be gutted and something put in there. What they choose to do could keep the spend down there, or drive it to the top of the range if they go with a real attraction. Personally I think it becomes a mall with some small attractions, so it probably goes to the bottom of the range. And then WoL if they bring it back, needs a full rebuild. The ride is long gone and after so long I can't imagine you can just tweak Cranium Command and retheme it to get it moving again. So those three pavilions alone, Imagination, UoE, and WoL are looking well over $1b. What they choose to do with Innoventions, updating the last scene of Spaceship Earth, redoing the graveyard and spine, updating Nemo which seems to be on the list, possible plussing in The Land, the Mission Space refurb which might have some plussing, all this stuff adds up with a few million to 100 million here and there and then it's another 500MM to 1B.
Then you talk about adding Rat, a few hundred million, a B/C in UK is going to be over 10MM, and 2 new pavilions? Plus a possible overlay for Mexico? Yeah. Close to a billion more in the back and that doesn't include International Gateway upgrades for the transport and something with the aging Illuminations.
So with all the rumors, hopes, and dreams, we are looking at 2-3B in my opinion. That's a lot of money. Think about it this way, EPCOT hosted 11.98 million guests in 2015. At $75 a pop (a few years back plus most people don't pay 1 day sticker price every day), that's less than $1B. So you are talking 2 to 3 years worth of ticket sales to pay for the things we are floating around.