We were there from 8/18 - 8/26 and visited Character Connection several times and talked to several CMs. What we were told is that Mickey, Pluto, Donald, Minnie and Chip-n-Dale are always "inside" but where you come on through the breezeway they always have about 2 characters present and it changes through out the day.
We were able to see Goofy, Max, Belle, Mary Poppins, Prince John, Cinderella, Alice, not sure of any others.
We had a funny story. My ds just loved this place and visiting the characters. We were there on 8/26 in the morning around 9:30, right when they open and we went in to see the main characters. Mickey started to run over to my ds and ds ran to him. Well, Mickey by mistake kicked my ds, Mickey's shoe went flying off, ds fell to the ground crying (not really hurt, just being a 5 yr old) well all the characters came over to him to see if he was ok and this is what I was able to get:
It's a shame that ds had to get kicked by Mickey to get a photo like this, but I might make him wear shin guards next trip and take a couple of more for the team