I thought up a story: Oswald, Ortensia and everyone else who eventually ends up in the wasteland once lived in Disney Kingdom until Xehanort, unseen, attackedand took their hearts so that the fated battle could happen exactly as it needed to. Yen Sid created the Wasteland (before it was called Wasteland) for those who lost their hearts so that they would not become heartless but they can no longer leave without their hearts, tying into the Epic Mickey plot, and Kingship was passed down to Mickey. Mickey was destroyed that his brother could never leave, although he and others can enter the land, so Mickey used the power of Yen Sid's brush in order to revive the hearts of the inhabitants which caused the Thinner Disaster. This would lead into the plot of Epic Mickey where Oswald and Ortensia are forced to fight the Blot and now the world is Wasteland. Oswald locked himself away in Mickeyjunk mountain (I can't come up with a good reason for it existing) in grief and hatred of his brother. And of course they can learn to love eachother again like in Epic Mickey.
Best I got for now!
