Well U/S has tons of inside rides. In fact I think they are all inside rides- so that is a good one in the rain. IOA not so good- with one of the best being the HULK, it is closed in rain. And they have other Roller coasters not to be missed. So skip that one. MGM has many inside rides as well- RNR, TOT, who wants to be a Millionare, Little mermaid, star tours, muppet 3d great movie ride....ect ect..That would be my first wet day pick.
In Epcot the problem you have is Future World in the rain and Test Track closes in rain as well. My kids would not want to miss that one so we would skip it on rain days.
Good luck and remember in FL rain sometimes means just a 30 minute shower. I'll hope for sunshine for you and have a great time.