Hope, don't assume that 7 month advance booking window is going to allow you to always get into other resorts at your chosen times
As example, you mentioned you are thinking about President's day week being a period when you might like to repeatedly stay at WDW.
That is a very high demand period, and unless you own at places like the Boardwalk and Beach Club (with a consequent 11 month advance booking window), you are going to get shut out of them if you try to book at the 7 month point. Frankly, the latter window is really only good for edge or off season bookings at those properties; the "prime time" is all spoken for by owners.
Really - I own at Boardwalk, and have found that to get what I want (which are not just prime but also some transitional periods like late spring and late summer), I not only have to book at 11 months, but on a day by day basis. It's that tight. The 7 month people competing with me for BW view 2Brs during those periods don't have a prayer.
Also, certain resorts have their own seasons which affect booking windows. As example, HH is very tough to get between June and late August if you don't own there, and Vero is similarly tough in the Spring.
Moral - buy where you think you are most frequently going to want to stay. With kids, I'd vote BWV, not SS.