Without watching the video, I'd suspect the answer has two parts.
1) They need it. In Japan, Halloween still isn't what it is here in the States. It's growing, but I'd imagine attendance lacks in Japan even more than it does here. Using Potter this way massively drives people to the park AND expands Halloween as a special event. But still, why did Japan get it before Orlando? Simple.
2) They asked. Previously, when asked why Orlando hadn't used Potter, A&D stated they hadn't asked. They haven't done HHN at Islands since 2005, long before Hogsmeade. Diagon is still a new, insanely attractive addition that doesn't need any plussing to get people through the gates. Orlando doesn't need Potter at HHN.