Thank you!
At some of the meals, there are celebrations or dances (these include CM, CP, and Tusker House). But for the most part, at WDW the characters just do the rotation. If it's slow in the restaurant, the characters might hang around longer.
My favorite character meal is CP dinner (I love the food). Now, it can get hectic here (it is a large restaurant). But I love it anyway. I also enjoy CM (I did the breakfast, but I want to try the dinner). 1900 Park Fare also seems to have good interaction (I've done dinner, and want to do breakfast).