Fantasy Faire has 2 sides, with 3 princesses on each side. You will only go on one side. The sign out front will tell you who is meeting guests. If a name appears on the sign, that princess is in there. If the name on the sign is blank, that means you will see a princess, but you don't know who. If meeting a particular princess is a priority and she isn't on the list, tell the CM at the entrance. They might be able to guide you down the right hallway if possible.
During the 24 hour party this year, I went to Fantasy Faire twice during the day and Ariel's Grotto for lunch. I was determined to see Sleeping Beauty (favorite Disney film) while I was dressed in my Jedi robes (other favorite movie). I wound up seeing Ariel, Cinderella, and Aurora at both locations. Belle, Snow White, and Tiana were unique to one location.
In all likelihood, you will see different friends of the same princess at both locations. But with just a few cues to the princess (like having your daughter thank the princess for having lunch with her or seeing her earlier that day) you will likely instantly create a situation where your daughter does not know the difference.
Let me illustrate. At Walt Disney World in 2009, I ate at Akershus in Epcot's Norway pavilion. Cinderella is rarely at Akershus since she's usually in her castle in Florida. However, on this night she was at Akershus and I asked her what Gus and Jaq were doing at the castle. She told me they were baking a cake and she hoped that the castle was still standing when she got back.
A couple of months later, I was at
Disneyland and saw Cinderella. I "refreshed" her memory of the earlier conversation and asked her what happened with the cake. Without skipping a beat, she told me that the mice had attempted to bake the cake out of cotton candy and it exploded leaving a huge mess in the kitchen. But since they were her friends and she loved them so much, she couldn't be too mad at them for making a mess.
Give the characters a chance to show you who they are and you will improve your chances of having a magical experience. I cannot believe how magical it was to have the princesses treat me like a Jedi Knight. I was just hoping to get some fun photos of me dressed as a Jedi with characters from some of my favorite Disney films. Little did I dream that they would treat me like I was a Jedi Knight. Made my day.