I think you'll have a great time.
Here is what I would suggest. Please note that Sea World doesn't take the planning that the Disney parks do.
There are just two roller coasters at Sea World (both very good). The Manta is the newest and there is also the Kraken. The lines for these tend to get longer during the day, so send those tall enough who like rides on the Manta first and then the Kracken. Others can look at some of the animal exhibits instead, and then all plan to meet up at a morning show. Get a show schedule when you get to the park or ahead of time from the net to pick the show to meet at. From there plan your day around the shows trying to get to the venue 15-20 minutes before the show starts. In between shows, see animal exhibits close to where you are. All the shows are good and worth doing, but I'd say the three must dos are 1) An Orca show (Believe or Shamu Rocks) -- I'm guessing most days in February probably just Believe will be offered // 2) Blue Horizons (the Dolphin show), and 3) the Clyde and Semour show (Sea Lion show). Definately get to the Clyde and Semour show early as there is a mime that is fun and entertaining to watch before the show starts. All the Animal Exhibits are well done and fun too. Shamu's Happy Harbor is a great play area (not just for little ones). I think your kids would love this. I'd skip the midway rides, though, in favor of the unique Sea World attractions. The animal exhibits are good to see any time with one exception. The Wild Artic (Short simulation ride or movie without simulation followed by great enclosed animal exhibits is special environment) will be extremely crowded right after any Orca show (It's right next to Shamu Stadium), so go to this any time other than right after an Orca show.
Have a wonderful time. We just love this park. I have active parents in their 70s, and they just love this place too.
) and shows, what is our best itinerary to see and do the "must see/do's"...
