I'm not sure why you would spend a whole day at AK. My children were 6 and 4 our last trip. We love AK, but we go there first thing in the morning, ride safari, do the two treks, see the Lion King show, and then we leave. Last trip, we also spent some time in Dinoland and the kids dug in the archeological site (WAY too young for your DS10). DD is 4 and Kali River Rapids and certainly Everest are out for her. Your DS10 might like them, but what do you do with the 6 and 4 year-old. BTW, if you do the rapids, be prepared to get soaked. Not just wet. Soaked.
After our morning in AK, we go to MGM and spend the rest of the day there. We ride Star Tours (not DD...she's not a thrill-ride person), Muppets 3D, Little Mermaid (probably not for you), the Indiana Jones show (your boys will love that), and see Fantasmic. Your older son, and probably not your 6 yo because there is a 50 inch height requirement, could ride Rockin Roller Coaster and TOT.
I would not skip Epcot. Soarin is a ride all of your boys could enjoy (the height requirement is 40 inches), and so is Test Track. Epcot is a great place to explore and since it is large, it doesn't seem as crowded or hot. This is our go-to park if we find our morning park getting crowded. Illuminations was my DS's favorite nighttime show. Fantasmic was DD's. The food at Epcot is also so varied that you can always find something to please everyone. Innoventions has lots of games DS10 could play if the younger boys wanted to do the character greet nearby. The lines for characters aren't as long in Epcot as they are in MK, and in the greet near Innoventions, you wait in one line and meet multiple characters. We saw Mickey, Minnie, Chip and Dale, Pluto and Goofy.
All the parks are special, and I think even if you only have three days, you can do all four.