A couple of suggestion, if I may:
-There was the idea (I believe it was ErikStormtrooper's) in the Starkiller Ranch thread that the 2nd Death Star was in construction over Mustafar. I that case I disagreed, as in its condition above Endor I didn't think it would be going anywhere. That said, if you're going to use a planet in the background of the DS1's into, why not Mustafar? The only drawback there I could see would be a lack of available "background plates" for the lava planet.
-While the "Imperial March" is an essential piece to be included, what do you think about retaining ANH's "Imperial Theme" througout the saga as the "Death Star Theme"? This way you could keep the ANH theme in the films, and mix up the music of the Empire a bit, as you wouldn't want to overplay the March.