I think that a doll costume would be cute, but so would a Princess costume. Halloween is for you kids and I think you should let them decide what to be. She will remember it always and you will be happy for the memories.
any costume to do with world championship
One should wear a maid sama costume and a cute wig that goes with it but not a hood.
If you are going door to door or a costume party-yes.
If an individual feels it is right to wear a certain costume, than he or she can. There should be no limitations to what an adult should wear as far as costumes are concerned. For a general idea of what an age-appropriate adult costume looks like, though, check out this site: http://kccbigcountry.hubpages.com/hub/Halloween-Costume-Ideas-to-Wear-to-Work
a horse costume.
a ghost costume or a ninja
The costume your teacher gives you!
whoopie cushion costume. be warned some kids might try to sit on you but that's okay
A bird costume would be easy, and lots of birds are yellow.
A barney the dinosaur costume.
Briefs