I really hope they don't turn Discoveryland into Star Wars Land.
It won't be all of Discoveryland, it would only be the rear portion of the land, most likely on the other side of the rail tracks as seen in the picture posted above. If we're really lucky, it will go outside the berm, but for now we'll assume it will stay inside the park confines.
With the exception of Space Mountain (which could have the Hyperspace Mountain overlay) I doubt they would do anything to the existing attractions. Maybe add Star Wars billboards to Autopia, but that's about it. Buzz isn't going anywhere, and neither is the Nautilus.
If they really had to, I don't see why they couldn't do it akin to Walt Disney Studios where you don't have to pay for that section of the park but you can in an all-inclusive park ticket. And although I do like Marvel, it would be the fairest way to deal with a Marvel Land also.
WDS is still a separate gate, requiring normal admission. Or do you mean that Star Wars Land would be classed as a separate gate whilst being part of Parc Disneyland (and therefore included in the park hopper?)
I can't see EuroDisney going for a boutique park - that model was rumoured for WDW, and if they decided not to do it, then Paris certainly won't.
I hope they do put another 4D film in Discoveryland in time for the 25th. Maybe even do something unique to DLP like show an entire already-existing hour and a half film in 4D?
Well they could just do it on the cheap and import the 'Pixar Short Film Festival' that has replaced HISTA at EPCOT. 90% of the Pixar shorts do not require any mulitlingual translations and therefore would be perfect for Paris.