ginny, I think the bus schedules can change depending on how busy it is at WDW. We go pretty much always during the off-season, and the buses go Swan to Dolphin to Yacht Club to Beach Club and sometimes the Boardwalk, which is why we stay usually at the Swan and if we are staying at the Dolphin, will walk over to the Swan to catch the bus there.
At Coronado Springs the buses have a set round of the bus stops at the resort and I am sure someone at the resort can tell you what they are. When we stayed at Port Orleans French Quarter the bus would stop at the one bus stop out in front of the French Quarter resort and then go from there to Port Orleans Riverside and make the rounds of the stops there before heading off to the parks. I would guess that Carribean Resort would have the same thing, but there will be one bus stop that the buses stop at first in the resorts with multiple bus stops before they go to the other stops and the CM's at the resorts should be able to tell you which bus stop is first.
When we stayed at the All Stars (off-season), the All Star Music and All Star Sports shared buses and (this was a few years ago)(smile), each resort had one bus stop and Sports was the first on and first off bus stop (bus would go to All Star Sports, pick up people and then go to All Star Music bus stop) while Movies had its own buses. I would bet that the people over on the Transportation Board would be able to answer any more specific questions.
And I think there are some roll-in shower rooms that are doubles, but I don't know for sure, since it is just my spouse and I and we have never needed an accessible double bed room. Sue will be along with the number to call (Special Services) and the people who work there are wonderful and hopefully they can answer any questions that you have.