Spas section was the last completed before Courts (now under renovation). Technically, Courts will be the freshest units as they complete, but as of last week when we left, none of the newly renovated Courts units were quite open yet. They were progressing pretty rapidly though; about 1/4 to 1/3 of Courts is currently closed. But honestly, I wouldn't worry about this at all. ALL of the units are relatively fresh, and they are all maintained to Sheraton standards.
Best pool for kids depends on the kids. On the South East part of the resort, Spas Super Pool is best for swimmers. Max depth is 4.5 feet in the middle, starting at 3 feet at either end. Kids can touch bottom through most of the pool. Cascades pool has a single step in at the shallow end, and there are several "humps" that protrude from the water with fountain jets. The whole area is no more than about 8" deep. The really little ones love the area. Cascades also has a waterfall that older kids like to play under. On the North West sector of the resort, there are two pools, at least one of which has zero entry and there is a slide as well if I recall (I don't often venture over to that side of the resort).