Cinderella, Snow White (sometimes Belle) and Aurora do share a room ... but it is not in the Judges Tent in Toontown ... that is where Mickey Mouse can be found ... I would hate for you to go to the Judges Tent and wait in line to see the Princesses only to find out at the end that it is Mickey ... not to dis Mickey by any means, he is the man (uh,mouse) and you def should go there and see him!
The Princesses, however, are at the Toontown Hall of Fame Tent inside County Bounty in Toontown (the store between Minnie's house and Mickey's house).
It is listed on the MK map, #33 in Toontown, with a Mickey hand noting it is a Character Meet-n-Greet area, and is listed as "Meet Disney Princesses and Characters."
** I would def suggest going there for a sure way to meet Cinderella, with the bonus of Snow White, Belle, or Aurora (Snow White and Belle take turns...we have only ever got to meet SW never Belle).
The very best time to go is during the last parade and fireworks. Toontown is practically empty then, as everyone is either trying to get in 1 last ride, catch that last parade and Wishes, or heading out to get to the TTC or buses before the crowd.
This was where we found Cinderella for our DD on our trip in 2002. We were there just to go through the line like everyone else and meet the Princesses. But to our surprise there was no line, only a CM at the end and the ropes closed off...we were so disappointed and thought that they had closed up already for the night. The CM confirmed it and said he would just let us walk on through to the end to exit...then to our surprise, he suddenly said to our DD, "Would you like to meet a Princess, Princess?" (she wore her little plastic crown everywhere that trip - she was 5), All of a sudden we went around a corner and there SHE was...Cinderella herself! You should have seen my DH and myself scrambbling for the camera and video. My daughter had a private audiance with Cinderella, autographs, pictures and some private time to talk...And the best part...it wasn't just Cinderella...ALL of the characters were there! So my DS got to see and get autographs also. We met: Minnie, Pluto, Pooh, Tigger, and Perla and Suzy (Cinderella's mice friends).
It was a magical moment... only at Disney!
After our visit with the Characters, which was quite long, we were not rushed at all, we were lead outside by the CM who asked us to wait in the courtyard in front of the store and shortly after all the characters came out and greeted us again and danced around with my DD and DS and then had a MnG with the other children that were there.