First: Sea World's show music is almost always produced exclusively for Sea World, and is rarely available in any form to the public.
Second: Background music is a slightly different story. I managed to get hold of one of the audio techs for the Orlando park once, because I was curious about some outstanding New Age instrumental stuff I'd heard through the walkway speakers. Turns out it was 99% off-the-shelf music from such artists as Pat Metheny, Michael Manring, George Winston, etc. I was able to track down everything I wanted from Ebay.
In short: Ask around! Don't take "I don't know" for an answer! Do as I did -- call Sea World, ask for the Audiovisual department. I'd be stunned if you couldn't find out what you wanted to know.
Walt Disney World
Tokyo Disney Resort