I've gone through the same thought processes that you have...with my 85 yo parents. Mom can't see well, Dad can't walk great, but he gets around, and both WALK through the parks, albeit slowly with many stops.
Some additional considerations...
If you are not in a HA unit, buy some portable grab bars at Bed, Bath and Beyond...they're wonderful if climbing into a tub/shower. Do they have a HA Parking Placard? Valet parking is free for those with the HA Placard, and most parking issues become a moot point, unless the drop-off is far from the
DVC resort itself (VWL comes to mind). There will be HA ramps near the valet drop-off.
1) Kidani- Will the carpeting "play tricks" on your mom's eyes with the animal skin pattern? Will the dark decor have the same effect? If she's ok with that, Kidani is a GREAT choice.
2) Jambo - While I haven't stayed there, I understand the tub/shower in the 1 BR is high and hard to step over. That is a definite consideration with the elderly. It would probably not be a wise choice. Also, the dark decor of the lobby would be tricky for depth perception. (Kidani is dark, too, but with a car you wouldn't have to go through the lobby much.)
3) SSR works real well with the elevator or first floor option. As others have mentioned, tell MS you need "near the bus stop and elevator for medical reasons." I have used that request at SSR and we were on the first floor in the front of the building.
4) OKW would work with the same request as SSR, but you said you'd like somewhere else for a change.
5) VWL, in my opinion, would be WAY too much walking (too far from the parking lot) and the dark decor plus patterns may "play tricks" on your mom's eyes.
6) BLT would be a good choice, but you'd need to request "near the SOUTH elevator bank/walkway for medical reasons" since anything else is a bit far to go to CR.
7) BCV seems to have parking that is closer, so that'd be ok maybe, but I don't know where the valet drop-off is there.
8) BWV would be ok, but request near the elevator...for the medical reason. Note that the boat dock is right out front of the resort.
We have stayed at SSR and BLT with my parents. Both worked well. I'm trying BWV in January with them, as the rooms are lighter color, everything is close, and the points are less. (We're point-challenged. BLT was a killer...3 of us in a studio.)
Good luck sorting it all out!