That's really common for littlies to be anxious around characters which aren't human...
I'd suggest you pick one or two characters, maybe mickey and pooh or something like that. Read lots of stories around those two, show her pictures etc... get her to 'know' them, then when she see's them for real they are less likely to be scary giant plastic faces, and more likely to be familiar faces, so she'll be happy to see them!
My daughter has never been one for cuddles with characters, she went to DLP for the first time age 2. She has got better with time, and lots of talking about the trips, and looking back at photos. She now will talk about 'Mickey Mouses house' very fondly, and when asked 'what shall we do today?' she'll often say either go to Paris, or to Disney Land. Always a positive step!
I'm sure you'll all have a lovely time! If you do nothing else, make sure you go to 'Playhouse disney live'......it's MUST see at that age!! Small world and dumbo, casey jr, & il pays (story boat next to casey jr) are also lovely at that age!
be wary that Pinocchio, snow white, peter pan, the haunted house, and pirates are all of a similar theme inside, i.e. if she's frightened by one, they'll all be scary, but if she can do one, then she'll be ok with them all I think! (add Buzz to that too....)