First off, let's preface all of this saying the story treatment here is very likely going to be a stretch. That's the opposition that most of us has.If Quill is visiting Epcot, why is there a Nova Corp building already there in Epcot?
I suspect it will be something like the Nova Corps setup shop in Epcot to showcase new technologies or something and they recruited the Guardians to tell the story of the ride (whatever that may be). As a heads up, this isn't that far off from the Wakanda motivation that I and others have suggested for Wonders of Life.
The obvious problem here is that historically the technologies showcased were grounded a bit more than super hero movies.