I am going to be a differing voice here - I vote for a 1 bedroom at SSR.
We're a family of 7 and my sister always travels with us, so party of 8.
I LOVE SSR, and I think your adult kids will appreciate the proximity to Disney Springs.
I don't get the "it doesn't feel as deluxe" opinions, personally. We stayed at AKL - Kidani, Savannah view and it was gorgeous and I loved it. But we heard EVERY noise in the hallways. The outside entrance makes you feel more secluded and it is more peaceful to me. But, of course, that is just my opinion.
But for sleeping arrangements, my family essentially take the 1 bedroom half and my sister the studio. Some of the kids will migrate in with her or us throughout the week as our kids are younger, but we've found we have plenty of room.