I agree with the PPs about Sea World.
The Zoo is going to be different! Have you read their disabled guest info on their website? Beyond that, I'd call and talk to someone about what specific areas you will have restricted access to or not be able to get into at all. The terrain in that area is hilly. There are mild hills, but I remember some that were pretty steep and a few long sets of stairs as well. There are signs that say that the zoo, due to it's terrain, cannot provide full access with guests with disabilities, or something like that.
The Wild Animal Park is more accessible, in my mind. We were there two weekends ago and I can't think that we ran across anything that would be a problem for a wheelchair.
Deb