First of all: Hello there.
This is my first post here, but ive been folowing adywans work here for a while. I hope i can do anything for help, im not too good with video editing, but ill try to help with everything i can.
First an idea, i know this has to do with Return of the Jedi, but also with Empire Strikes Back, and is easier to change in Empire.
This shot was added for the special edition and appears on Empire when Lando is warning the city to evacuate, and in Jedi at the ending celebration. Since in Return of the Jedi it is a pan shot, with crowd cheering, i guess its easier to change it (or substitute it) on ESB (Or tweak it in some way on ROTJ, like changing the sky, i dont know)
Then, I have made a little test about the hologram of the Emperor on ESB. There is just one shot where the Emperor actually speaks seen from the side "Can it be done". Since it would be hard to use the eyes from ROTJ and the mouth from the DVD for that side shot, i have found this moment on ROTJ when he says "and when he does" and it kinda fits with "can it be done".
Since the hologram will have distorsions, you wont see that the mouth doesnt fit with what he says, nor that he is "frozen" when he doesnt speak.
http://www.youtube.com/watch?v=LpvstrolYU8
I know, its not very well done... The emperor is steady as his hologram should be (thats why the background moves, because he was walking there)