Have you looked at the crowd calendars at
www.easywdw.com. I really liked the explanations there and preferred them to touringplans.com
From a quick scan of your itinerary, I would flip-flop Days 4 & 5. DHS will be much less crowded on Day 5. Most of the parks look busy on Day 4, so you might as well rest that day instead.
Is your family interested in Star Wars? If so, DHS is hosting Star Wars weekends, and Josh at easyWDW recommends going on a Sunday (the least crowded of an extremely crowded weekend).
I don't think you need the hopper tickets, especially since you are planning to go back early each night to put the kids to bed. We had hoppers in early December and used them quite a bit, but WDW is huge, and hopping from park to park takes a long time. You can always add the hoppers at the park if you decide you need them--no need to buy them now.
I would suggest posting on the easyWDW boards for itinerary/touring plan help. The boards there are much smaller than the DIS boards but easier to navigate, and the experts there are very friendly and helpful.
Have fun!