First of all, picture me at age 50 with naturally pure white hair. Got that? OK......Then you know I am already in character....
I made myself a Fairy Godmother costume a few years ago and have worn it a couple of times to MNSSHP. I was approached by several kids with autograph books, parents asked me to pose with kids (they knew the reality, but try to tell the kids that). One man was so nice, his daughter was crying because she wanted to come see me.......I had a great time joking with Cruella about her attitude and told everyone who commented on my costume to check out the pumpkin I turned into a coach in the back of the castle and told them I was looking for volunteers for horses....The CM that was escorting Merlin spotted me and he looked and said "She looks just like Lily" (must be their first name for the FG?)and we talked about Magic and how old we were and then he posed for a pic with me...It was a fun, fun night......
I even wore it during the afternoon snowglobe parade once. I was standing up and filming it and the walking characters would bow or stop and wave and then when the princess float came, Prince Charming spotted me, turned and tapped Cinderella (who was facing the other way) on the shoulder and she then turned and they both waved......and then one of the mice spotted me and got all excited and got the other one to turn and they both waved..... I have it all on tape. So cute.
And the woman next to me (who happened to be Deb Wills from WDWIG, what a nice surprise) her grand-daughter sat with me before the parade. She was just glued right on me. It was very charming. I got a real taste of how much kids believe, being on the other side of the costume. It's one thing to watch it, another thing entirely to be the object of the belief.
Man, who says Disney is for kids!!!!!
Anyway - back to your question - this year, my DGD8 will be Cinderella, DSD33 will be Snow White, DF10 will be Dopey and DGS5 might be Maleficent as a dragon, or Buzz, or Mickey. You know, it changes daily......
My advice is - play up your character - it really adds to the fun!