My take on this based on my own DS17 is that while many kids grow out of irrational fears. There might be something particularly triggery they may never get over. For example my son still freaks out about Charlie & the Chocolate Factory. It's always bothered him and still does. But I haven't seen him get any new phobia's. Then again he may just have learned how to avoid what bothers him, I've never seen him watch a horror movie either.
As to Disney. It is quite possible to go to Disney and never get close to any of the characters. Although you probably will see some from afar particularly if they watch a parade. (Honestly I don't know what the fuss is about, what's the big deal about getting a picture with a costumed character.) When my kids were younger we went to Disney 1-3 times a year. But we spend our time most on the rides. As chay says they are really fairly easy to avoid.
