Yes Storyteller's does MYO pizza and besides that there is the MYO peanut butter and jelly in DL. I don't know of any desserts anywhere, although that would be great!
Kids can make their own pb&j sandwich at the Carnation Cafe--one of the reasons why we love to eat there every trip (in addition to the loaded baked potato soup!!!)
No, characters are only at breakfast. And I have to second that make your own pbj at Carnation Cafe. It comes out on an artist's palette so they really do like they are creating a work of art. My dd loved that one!