The thing is, with first-timers, Magic Kingdom is
the park to visit - it's the castle, has the most attractions, what they continuously see in advertising. Pushing that to the end of your trip may be hard for the kids (or child-like adults
).
Knowing what I do know about your trip I would do:
AK (Monday - makes sense since you're going to be AKL; definitely take advantage of that proximity. Also will probably have the lowest crowds of all parks on a holiday weekend), Magic Kingdom, resort day, HS, Epcot, resort day, Magic Kingdom
I know that you want to be flexible on your repeat park day, but I would highly suggest of booking a park reservation in case all parks sell out (we saw this happen for a few weeks during Spring Break crowds this year). I suggest Magic Kingdom because it has the most attractions, so in case you miss any on your first MK day you can catch them on your second day. On your second resort day you guys can discuss if you want to keep MK or change it to another park.
BUT, if you have big Star Wars fans in your group, I would suggest HS as your repeat resort day so you have more opportunities to get Rise of the Resistance boarding groups.