If the negatives are too degraded, I think Mike Verta's route of using 35 mm prints would be the most logical. Since they are probably in the process of converting the OT to 3D like the PT, the Reliance project is most likely based on the '97 negative. They wil need to redo/update the 2004/2011 changes, and redo the color grading. My guess is that this is being done under GL's supervision, since I can't see them altering any of the films without his blessing.

All three films could be released in theatres in 3D for the 40th anniversary, followed by a deluxe 3D bluray boxset, that may or may not contain the originals. They might even release Legacy to test the waters next year, and then restore the other two for the 2017 bluray set, if Legacy is successful. Alternatively they might keep Legacy under wraps until 2017, and release it together with the others as bonus material. This is all speculation of course.