Star Tours is more of a problem for those prone to motion sickness. It’s not scary, and I’ve seen kids much younger than six go on it and love it.
Animal Kingdom is the easiest park to miss if you have to miss one. Somehow, it’s always hotter there than anywhere else on the resort. Also, it’s definitely more of a leisurely, walk around and appreciate the themeing type of experience than if you’re looking to hop from ride to ride. It’s very kid-friendly, though – there are parades, animals all over the place, and character greeting areas.
However, if you do go (and with seven days, you should have plenty of time to), the Kilimanjaro Safaris are a must-see, if you go early in the day. Kids will also like the Lion King show, which has live performers and acrobats and is impressive. “Tarzan Rocks,” however, doesn’t. The raft ride is not worth it. Neither is the train ride to “Conservation Station,” unless you have someone in your party who’s really interested in animal care. The Dinosaur ride (which I can’t remember if it’s open or not) is neat, but can be scary for younger kids. And the Tree of Life contains the “It’s Tough to Be a Bug” 3-D movie, which is outstanding, but can also be scary for young children.
MGM is my second-favorite of the parks, next to Epcot. And that’s only because of the Tower of Terror, which is IMO the best thing Disney has ever done. It’s a combination of a freefall ride and the Haunted Mansion. I couldn’t guess the age limits for that, but I know that the last time I went, a man was taking his son and daughter on the ride, and she kept proudly telling everyone that she was 5 years old and it was her favorite ride. MGM also has a “Stars and Motorcars” parade that’s popular with kids and antique-car-buff adults.
I’ve never been to Typhoon Lagoon, but Blizzard Beach is a lot of fun for a half-day.
And the absolute must-see thing at the park is at Epcot, the “Illuminations” fireworks show around the World Showcase Lagoon. It’s outstanding.