This is where my passporter has come in handy! We chose Blizzard Beach because it scored the highest overall in reader reviews, but here's why I would choose it for your family:
1) Tike's Peak--mini version of the park. Must be 48" or under, ages 0-6
2) Ski Patrol Training Camp--Scaled-down area for kid 12 and under.
Typhoon Lagoon seems to be aimed at slightly older kids, though both seem very family friendly.