I just asked this question about 2 weeks ago on this very thread! I'll tell you some of the repeat answers I got:
Snow White scared almost every 2.5 yo.
MOST went back to nap at the hotel in order to come back and enjoy the nightlife.
It's Tough To Be A Bug scared every one that responded.
Pooh and Peter Pan were the top fav's of almost all the 2.5 yo.
I was worried my 2.5 yo son wouldn't be into any of the shows, which I am really into. but almost everyone said the 2.5 yo loved the shows!
I was also worried about characters scaring my son. About 70% said the characters didn't scare their kids (but that means 30% were scared!!). We're still doing a character breakfast to test the waters....
They ALL said to get to the parks at rope drop....kids are up so early anyways!!
One mom suggested really getting her little one familiar w/ the characters by watching a lot of Disney movies a few months before the trips. Obviously, it's up to you which ones you allow her to watch....
I just ordered "The Unofficial Guide to WDW with kids," off of Amazon.com for $8!! It was recommended to me by more than two people, so I'l pass that on to you.
Have fun, and every single person told me to let my child set the pace. To have a plan, but to be super flexible with it and go with the flow. Better to have a happy child waiting in a line for a ride that he/she wants to go on, rather than a grumpy child waiting in a line that is in "the plan." KWIM??