They vary from day to day- but here is a general idea:
Minnie and friends at the Plaza: Minnie, Pooh, Tigger, Eeyore, Capt Hook, Fairy Godmother, Chip and Dale- sometimes a couple of them are replaced with someone else.
Storytellers at GC: Chip and Dale, Koda and Kenai (sp?) from Brother bear, Meeko, other various "woodsy" characters. Very low key interaction
Ariels at DCA: Princesses, usually 5, and always Ariel (with her human legs).
Goofys at the DCA: Various, our last trip was Aladin, Donald, Max, Goofy, and Snow White. Pluto was out front for pictures.
Lilo and Stitch at PP: Typically Lilo, Stitch, Minnie, Pluto and Daisy.
If you are looking for Mickey, you wont usually find him at a meal. But you can find him at the birthday celebration at the plaza.