Personally I would either use live elements, or if they have cuts from the film soundtrack in the queue, OR if anywhere in the ride they have elements that could be found on officially released discs....Id use that.
Have you been on Stitch? What kinds of music do they have in the queue and the attractions itself? Maybe you could piece together a "hand made" music track if they use cuts from the soundtrack.
The queue doesn't have any music unless you count the Tomorrowland area loop since its all outside, but I believe there is preshow music thats probably all new for the attraction. I'd agree with s8ntmark the best thing to do is use a live recording, cause right now there is nothing from this attraction not live.