It'd definitely possible to do Disney in 3 days. You won't be able to do it all, but you wouldn't be able to do it all in 10 days, so just focus on what you can do.
If I were you, I would start with/priotitize Animal Kingdom and Studios because those two parks have the attractions that are most unique to Florida. You've visited
Disneyland several times before, so many of the rides in Magic Kingdom will be a rehash for you and the kids; and Soarin' and Fast track are the biggest draws for boys in Epcot and you've already got Soarin' in Cali, and Test Track (IMHO) isn't as good as radiator springs.
So I would do Animal Kingdom day one. If you find you've done all you want to do in that park and you still have time in the day, THEN get a hopper.You can always upgrade while you're there IF you need it.
Day two I would do Studios. Assuming you didn't upgrade to hoppers on day one, if you find you have time left over after doing all you want to do in Studios, then upgrade and head over to EPCOT. Mission Space doesn't get a lot of love but I think 8 and 10 year old boys would love it. The Frozen ride is something they'd probably like too. If you keep refreshing FP you've got at least a decent chance of snagging one.
Day three I'd do MK. Hit the uniquely Florida rides and/or hop to other parks to tie up any loose ends.
I'd use the website to start looking over the attractions in each park with the kids as soon as possible, so you get an idea of what they like and want to do. This will give you a better idea of exactly what your time in each park might look like.
