I wouldn't worry about the weather, you have to wear wetsuits and you spend most of your time in the water. The salt water lagoon is freezing even if it is hot outside...We did it in October and thoroughly enjoyed it.
Discovery Cove is the best day you will have in Orlando. We have been there in February, and you will enjoy the wetsuits in the water with the dolphins, which is kept colder for them. The rest of the water in the pools and river is much warmer; wetsuit optional. November is a great time to go to Orlando, the humidity is letting up but the days are still plenty warm. Unlike other theme parks, you will want to make a reservation before your trip to make sure you get in to Discovery Cove, which has limited admission.