The characters at Liberty Tree Tavern are "Minnie and Friends". Minnie is almost always there and is joined by a few other characters that seem to varry from night to night. Pluto is a pretty common character to find there as well. Other characters seem to varry greatly. Past characters at the meal in the past few months have included Chip, Dale, Meeko (the racoon from Pocahontas), Goofy, Max (Goofy's son), Donald, Daisy, Suzy and Perla (mice from Cinderella) or other characters. Which 3 or so characters out of that group you will see, however, you most likely will not know until you get there.