As ridiculous as it sounds, there seems to be a timeline to the games that Disney puts out.
In "Kingdom Hearts 2", we get a flashback via Timeless River to a time where the toons were just toons. And in that flashback, we see Mickey when he was still more chaotic and reckless, as well as his house. Flash forward five years, and "Epic Mickey" comes out. In that, it starts with the classic "Thru the Mirror" short. However, Mickey ends up in Yen Sid's tower, and as such, if you get the good ending of the game, the timeline fits better. After that, Yen Sid takes on Mickey as his apprentice, as we see in Fantasia. (I know it isn't a game but it fits in the timeline) Over some time, Mickey gains the ability to wield the keyblade, and we get the rest of the Kingdom Hearts timeline from "Birth By Sleep" onward.