Also... remember that if the characters are being too abrupt for your children, you can ask them to tone it down. I have always found the characters to be very respectful of parents wishes when the kids are getting upset... especially the face characters that are allowed to speak. You can also redirect the interaction to yourself as opposed to your children if they are feeling intimidated.
We did this dinner about 18 months ago when it was still Suzy and Perla there. My DD had a BBB makeover and went as Cinderella. She got lots of special attention from the characters, and Prince Charming asked her to dance! BUT... if your DD is easily intimidated, that may be too much for her too handle. I can only imagine the attention she would get from the steps if she went dressed up!