There usually is about 5 characters for each Character Meal. Some restaurants will have less, others will have more.
The ones that I know :
1900 Park Fare - Breakfast : ''English'' characters like Alice, Mad Hatter, Mary Poppins, Pooh and friends
1900 Park Fare - Dinner : Usually Cinderella, Prince Charming, Lady Tremaine and Step Sisters
Crystal Palace : Pooh, Tigger, Eeyore and Piglet
Tusker House : Donald, Mickey, Gooffy, Minnie, Daisy and Pluto in safari outfit
Akershus Banquet : Belle, Snow White, Aurora and Jasmine
Cape May Café : Mickey, Minnie, Pluto and Goofy in beach outfit
Hollywood and Vine : Disney Junior Characters
Ohana : Lilo, Stitch, Mickey and Pluto
Chef Mickey : Different classic characters
Of course, it can always change!