I have stayed at the S/D, and had my name on a friends room reservation at the BW before. Never an issue. But, she was the only one on her reservation, so adding me was no issue. Since you are using the
DDP, won't be able to do that. Everyone on the reservation needs to have the same stuff....so it would cost a lot.
I really recommend the Mears shuttle. I've used it before, in the interest of gathering decent info for this board. It isn't as quick as DME, but it will get them there. Takes 90 mins or so. The bus will make stops at non-WDW resorts along the way...it's kind of interesting to see the other resorts in Orlando.
If your friends want a more direct ride, then a car service will work out best. That will run about $115 plus tip, r/t vs about $65 for 2 to use the Mears shuttle r/t...plus tip.