Honestly, the Disney themed thing won't drive it up much--if they're having fun, wonderful. It will probably reduce it compared to a "normal" wedding since flowers are so stupidly expensive, and you can probably sell a lot of it later, or else keep some of the stuff. Good luck doing that with a tulip.
I guess I shouldn't talk, since I'm having a perfectly unmustachian wedding. Some of that is my fault, since I really wanted all my family there and it is a big family. Most of it is not--apparently you can't cheap out on the flowers. And we're NOT doing a buffet, that just won't fly. And that place was not nice enough, the carpets were old! and....
Thank God my fiance picked up her dads source of happiness and not her moms. But that really isn't fair, it really is not her fault.