It's real, but its full name is
Disney Music Group, or the DMG. Most of the Kingdom Hearts soundtracks are released under
Walt Disney Records, one of its subsidiaries. Which poses another question - is Walt Disney Records autonomous enough that any request to use KH music would go to them, or is that decision up to the DMG? Note that WDR's distributor is Universal Music Group. Would they have to be involved somehow as well?
All questions I have no answer to, as I know nothing about the industry in question.