Children annual passes do not include free parking.
The best way to purchase tickets, is buy one adult annual pass, and use it to get a $7 discount on each additional ticket. If you're Florida residents, for about the same price, you can get the Fun Card, it allows entry into the one park for the remainder of the year. So the adult annual pass will get you the discounts (10% on food and merchandise), free parking, and sometimes other perks or discounts. Last year they were allowing each passport member to bring one person in for free, each additional person would get a $20 discount. The summer before they gave out coupon cards, that had B1G1 free meals, free ride photos, and additional discounts on things.
If you're only visiting for one or two days, the second day is free with a one day ticket (even if you use the discount). The next option allows 14 days of unlimited entry into the park, and for a small fee you can add Aquatica.
While Aquatica is not as large as Disney's water parks, it is fun and a ton to do in a day. Often times, I would go at about 4 or 5 in the afternoon and stay till closing in the summer time. More than 1/2 the park would clear out by dinner time, sunburnt, sore and tired. That late in the afternoon, you have almost the whole park to yourself, and the sun isn't as hot to burn your feet on the ground or give you a sunburn (unless you're really prone to it). Plus what would take 2-3hrs to do in the middle of the day only takes about an hour to do at night time since there's no lines.
As for feedings:
Dolphins - There's a place to stand on the other side of the lagoon if you have a good zoom on your camera. Every one that enters into the feeding area must pay for a tray of food. With a passport discount, it's about $7 vs $8 for every one else. There will also be photographers taking your photo too, which you can see as you exit the area.
There is a non feeding side to the dolphin cove, but they're smart, they know where the fish are. Sometimes you can stand there for about 2-3 hrs before actually touching a dolphin. Been there, done that.
If you would like to avoid it all together, walk past the dolphin cove to the stadium and on the backside is the underwater viewing area. They swim by the windows often and it's another great up close moment (without the disappoint of not being able to touch, or too scared when feeding)
Sting Rays - You do not need to purchase food to pet the sting rays. And truthfully, many people (kids and adults) get terrified when it comes to feeding them and do it wrong. You're to put your hand on the bottom of the tank and let the ray glide over sucking the food into their mouth. People get scared and don't put their hand in the water far enough or try to pull out as a ray gets close, this causes the ray to try and jump out of the water flapping and splashing a lot of water, which only adds to the fear.
Just put you're hand a few inches into the water, and let the ray glide under your hand. It's soft, squishy, and slimy, but plenty of rays to touch and they're not picky like the dolphins.
Sea Lions and Seals - You stand on an elevated pathway around Pacific Point with them below you. There is no up close interaction with them, and the birds are sitting right next to them looking for their next meal too. (same with the dolphins, the birds get in a frenzy when the feeding starts and will snatch from your hand and tray if you're not careful). If you do decide to feed, you toss the food over and hope you have a good catcher.
You can also feed the sharks and fish in front of Shark Encounters. Just toss over the railing, the birds aren't quite in a frenzy here.
Some other must see animal areas:
Wild Artic - there is a walking and a helicopter entrance into this one. The helicopter version is like Star Tours, you ride a helicopter from the base to Wild Artic with a few ups and downs along the way. The walking version is the same exact movie shown in a room with bench seating, so you don't get that whole "flying feeling". If you do buy an annual pass, in the gift shop, left of the exit is a "Passport Members Only" entrance, it takes you to the beginning of Wild Artic, but on the other side of the ride.
When you enter, you see the Beluga Whales, and they also have private tours, so you can often see guests on the other side interacting with the whales. Next is the Polar Bear, of like 3 years of having an annual pass, I saw them up and playing maybe 3 or 4 times. Most the time you'll see them snoozing. But they are ohh so cute. After the whales are the walruses. They're usually swimming around. Just don't be surprised if the males are a little happy showing off in front of the glass. (if you get my drift...)
As you move further on, you go to the underwater viewing area.
Manta Aquarium - It's an under water look at the sting rays and a few other large fish. I don't know if they've gotten a new Pacific Octopus or not, but the last one was really cool to look at. There's also several other small salt water tanks, including one at the entrance with a huge coral reef collection. The one at the end allows kids to go underneath and put their head in the middle of the tank, another great picture opportunity.
Shark Encounters - An awesome moving walkway through a tunnel in the shark tank. There's also lots of other cool exhibits as you walk in.
Penguin Encounters - My favorite, I can spend hours there watching, and that's also how I got the picture in my sig. Every day at 2pm, there's a Penguin Talks, a trainer comes out to talk with the audience with a Q&A session. At the end, the trainer asks one question and the first person with the correct answer will win a chance to go backstage with their family to meet one of the penguins. BTW, it's FREEZING in there. But they're so soft and cute. Ohh and the "penguin chatter" you hear while viewing them, is a prerecorded chatter, it sounds a lot different inside. Don't forget to say hi to the Puffins.
There's plenty of other animal encounter and viewing areas, but those are the highlights.
As for the shows, it's not really possible to see all of them in one day. So plan accordingly. Sea World will put up it's show times at the beginning of each month. If you're going during the summer, and don't really want to deal with the mass exit, skip the fireworks, they're not that grand.
Ohh yeah, the sky tower is a really cool view of Orlando and the parks, but it's about $3 per person.