Yes, DVC can book it but through MS. I just called last week for our June trip and now have to call and change our departure resort.
As far as wait times go...someone came out with this and it makes sense...the bus holds approx. 57 people. Divide this by 4 (average family) and you get 17 parties going to their particular resort. So, if ME puts the MK resorts together, you would be making, maybe 3, stops, with 5 families getting off at each one..theoretically. But, if most of the people are going to the Polynesian then your wait time is even less. No luggage will have to be taken off the bus, slowing you down. It will be just like taking the park buses.
And yes, Mears is driving the buses but there it stops. Disney is running the show, so to speak. They know exactly who is coming in at what time and where they are going. This way they can plan ahead as to what bus they will need. Not like Mears that just filled 'em up and went. Sometimes you had to sit there, on the bus, waiting for others to come in order to have a fuller bus. And that could take a long time. Now, you get met by a Disney rep, taken to a central disbursing area, put on a bus and off you go.
I don't think there will be more than 3 stops, at most, for each bus run. I would think it wouldn't take more than an hour to get to your resort. And that's what I always figure on when I book a towncar service.