I thoroughly enjoyed the Epic Mickey game. The story really caters to the Disney Fan. The look and feel of the Wasteland is a perfect fit for a Disney Halloween Overlay. Its has the creepy vibe in each of the worlds, but not enough to scare the kiddies.
It can be the entire park or just some areas like matterhorn can be converted to Mickey Junk Mountain by including large replicas of old mickey mouse products in and around the Mountain.
Light projections can be used to simulate paint thinner and paint on the walls of mainstreet. Oswald can finally make an appearance alongside mickey both looking like themselves in the game during a parade or using the Fantasmic stage in Rivers of America
Disneyland can have their first walking "monsters" in the park, using the enemies and altered characters in the game. "of course they won't go scaring little kids, their just their for the atmosphere. The Mad Doctor can make his first appearance (I think) as a costumed character.
If the whole parks idea is a little too much then at least they can probably keep it in Toontown. Give it that same twisted look in the game and have classic disney characters come out. of course also have those light projections to simulate paint and paint thinner.
Since the Second game and a handheld version is coming out Disney has the perfect opportunity to promote the game, and also add a whole new overlay during the Halloween Celebration.