We have stayed at the BCV and the BWV many times while on the DDP. We loved it. We used wegoshop.com to deliver coffee, juice, water, soda, beer, wine, and snacks. We ate a light breakfast in the Villas and usually a CS lunch and a TS dinner on the dining plan.
Yes you can! Just contact the member you are renting from and tell them you want to add the DDP. They have to call and add it to your ressie. This needs to be done 48 hours in advance of your trip. You pay for it at the resort and you have to have it for as many nights as you are staying and for everyone staying in the room. You do not have to purchase park passes with it like when you have a package at a regular Disney resort.