The Pixar characters are a different thing ... even though Disney owns Pixar, part of that deal is that Pixar has total control of how its characters are used, for how long, and in what types of formats. And sometimes Pixar does say "no", based on where and how the character is presented. They don't want anything that will dilute the story.
Buzz, for example, used to just be on the balcony of Tomorrowland, near his ride. In that location, Pixar would not allow Disney to set up Photopass because the background (regular old Tomorrowland facade) was not appropriate. Once Disney re-designed and built a background appropriate to the story of Buzz, the Photopass was allowed to utilize that area.