Yes you can get the dining plan as a renter. The owner you rent from will have to make the arrangements for you, and you will pay for the dining plan at checkin. If you are staying at a DVC resort on a points reservation, you do not have to buy park tickets in order to qualify for the dining plan.
For 2007, you can get the dining plan. We don't know about 2008 yet.
The person you rent from will have to call member services and tell them to add the dining plan to your reservation. You will pay for the plan when you check in. By going through DVC, you pay the same price for the dinning plan, but you aren't required to buy any park tickets.
Yes, renter can stillthe DDP for 2008. In fact, you have your choice of the standard DDP or Deluxe DDP. Standard plan is $38 per night per adult, $10 per child 3 to 9 years old. Deluxe is $70 per adult and $20 per child.
Neither plan includes server gratuities for 2008, so you're looking at an extra 15% to 20% out of pocket.