The older sections in Vistana and Sabal or quite similar.
When booking, make sure you get a sleeps 8 configuration to ensure enough beds for all. IMO Springs might be a best fit for your wish list; the Springs pool is generally pretty quiet, and still close to the action at the Cascades or Spas pool for the kids. These are 3 storey walkup buildings. Spas (2-3 storey) or Fountains (3 storey) would also be a good fit. The newer Cascades and Lakes Sections are probably higher density than you would want.
You don't generally get a choice of sections when booking (although VIO will probably give you a better chance at Fountains over VIT); both RCI and II reservations are assigned "run of house" from the pool of available villas that match the reservation criteria. The resort has a Diamond Lane request (link on page 1) which generally triggers a call from a concierge and gives access to Diamond Lane check in. You can make a request for a section from the resort, through the concierge and they do their best to accommodate within the villa class reserved.
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