Hi Genevieve,
You are going to have a great vacation! I love traveling with family and friends.
Since you do not mention when you are arriving or leaving the Walt Disney World Resorts, I count you have four full days. You will need at least a full day in all of the parks. However, Animal Kingdom could be finished in about eight hours so you could visit another park later in the day if you have a Magic Your Way with Park Hopper Option ticket.
I would have a conversation with the other adults about how much you want to do on this trip. Often guests plan so much into a trip they do not enjoy it. If it is the first trip for most in the group, I would concentrate on one day per park. This will allow you to enjoy that park and not worry about going to another park.
As for a character dinner, my favorite is
Cinderella's Happily Ever After Dinner at 1900 Park Fare in the Grand Floridian. It is a fun buffet and the step sisters make it so worth the experience.
If you want a non-princess dinner,
The Crystal Palace and Winnie the Pooh would be my next choice.
Wishing you a magical vacation!
Beth