Hi Steven, the magic is just around the corner for you and your family and I'm sure all of you are getting super excited.
First is
Wilderness Explorers at Disney's Animal Kingdom. This happened to be my daughter's absolute favorite activity during our trip last summer. She was 6 at the time and had a blast on this scavenger-hunt, badge (sticker) collecting activity. It is of no extra cost as it is included in the price of admission. They can learn all about cultures, animals and traditions all while enjoying the parks at the same time. If there was a ride that my daughter couldn't ride (ie, Expedition Everest), she would find the nearby activity station to "earn" her badge while big brother went on the ride. Over at Epcot are the
Kidcot Fun Stops around World Showcase that I'm sure all three will love! This is a fun way for them to experience the culture of those countries at a level they can understand and enjoy. Also at Epcot is
Agent P's World Showcase Adventure. This might be more for your oldest boy, but when my daughter was 3, she also had fun tagging along with brother as she wanted to "save the world", too! The little ones might not completely "get it", but it is a great interactive activity to see different parts of the World Showcase. Disney Junior - Live on Stage was my 2 year old's favorite. It showcased his favorite characters in a cute show over at Disney's Hollywood Studios!
Don't forget about the amazing parades and other shows at all of the parks, as these are perfect opportunities to sit and take a much needed break during the day. Be sure to check the times guides for times and locations.
Have an amazing trip!
~Allison L