Going to be at Disney for 7 days with dd6, dd4, and dh. Was planing one day at animal kingdom and one day at Hollywood studios. Would u do two Epcot days and two Mk days or 1 Epcot day and 3 mk days?
The adults will love Epcot. The kids will love MK. The adults will love seeing how excited the kids are at MK. Even though I much prefer Epcot with your particular group I think 2 days at MK and 1 at EP is likely to be the better fit. That's only 5 days though and it is very cheap to add a day to the ticket if you decide mid stream you'd like another day at Epcot.
If you want to hit all 3 Epcot headliners (Test Track, Soarin' & Frozen Ever After) it will be far easier to do over 2 days if you hope to avoid lines. The kids I'm sure will enjoy MK more overall - if it was me, I'd park hop and catch one of the headliners on an eat at Epcot day and do 2+ days at MK. But that would depend on if you have park hoppers or not. And if you're not interested in Frozen, doing Soarin' & TT in 1 day shouldn't be an issue...
I would consider skipping HS. We went with DDs 6 and 3. We had plans of hitting every park but ended up sticking to MK and Epcot. Nobody felt like they were missing anything. At this age I'd rather spend time with them in MK where there's so much for them to enjoy. There's always more to do than you can reasonably fit in; enjoy the little kid stuff this trip and save some of the other stuff for another year.
We have a 7 day trip planned for Jan 2017 with our dds 8 and 4, and DS 1. I am tentatively scheduling 1 day at EPCOT, AK and HS ( and one day for dh and dd8 at UNI) and 2 at MK with our last day tbd. I expect to be at EPCOT on the last day but I am just not sure what the family will want. I think it will be a Toss between EPCOT and MK for the last day.
Note: my touring plan for our EPCOT day does get in essentially all that the kids would want to see so I am treating our last day as an anything goes kinda day.