Hi Lisa!
What a fabulous trip you've got planned! You are going to have such a lovely time at the Animal Kingdom Lodge with your family. And your son and future daughter-in-law are lucky to have you plan this for them.
The answer to how many "days" the dining plan must be purchased is based on
nights per room reservation. If your son and his fiancé have their own room for 5 nights then their dining plan will be for 5 nights. If however they are sharing a room with you and that room reservation is for 7 nights, then everyone will have the dining plan for 7 nights.
If your son and fiancé have the 7 night dining plan but are only staying for 5 nights, it still doesn't have to be a loss for you. I suggest having them reserve some special 2 table credit meals, like
Jiko - the Cooking Place. You might even surprise them with romantic dinner reservations for just the two of them. To view other
Signature Dining Locations visit this link and select the filters for "Fine/Signature Dining" and "2014 Dining Plan".
I hope this information helps you in planning your upcoming vacation Lisa. If you have any more questions, please come back and visit us at the Disney Parks Moms Panel. We love to help!
Blessings,
Brenda ºOº