Disney's feasibility/approval process happens fairly early in the design process. It is after Blue Sky and Concept Design, leaving Schematic Design, Design Development and Construction Documentation to occur afterwards. While something like the Rattouille attraction would have most of its design intent already settled, you cannot simply grab blueprints for a building in France and hand them to a contractor in Florida. There are lots of technical details that will have to be reviewed and redesigned by architects and engineers licensed in Florida. Every little thing has to reviewed to ensure that it is in compliance with the EPCOT Building Code. The back wall of the showbuilding in France may not meet EPCOT's wind load requirements. Walls designed to be built with standard European metric material dimensions may have to be redesigned for American imperial dimensions. Doors checked for egress size and accessibility. The slope of roofs. Electrical wiring needs to be designed for American loads. HVAC needs to be designed for Florida's very different climate. Lots of little things that all go into something that looks the same.
A great example of this is the Twilight Zone Tower of Terror at Disney's California Adventure and Walt Disney Studios Park. If you look at construction photos of the two, you will see that, despite having the same outward appearance, they are completely different structural systems.