You might be able to do that. It is worth a try. I just booked an AoA family suite using the Disney Visa card, but here is the kicker: I was told that when I use the Disney Visa card for the discount (we are doing the room only discount) I can't choose which family suite I want to stay in. Could be Cars, Lion King, or Finding Nemo. I am not sure if that is the case for
free dining as well as for the room only discount.
If they let you do it without your being in the room, you might have to cancel her reservation, put the deposit on the room using the Disney Visa card with a new reservation, and she might not get a guaranteed Cars suite. That is my best guest, based on how my reservation was handled.
It would be worth calling and discussing with a cast member on the best way to handle it.
If you can't do it for her, that offer should be available to her when the offer opens up to the general public on May 7th, provided there is still promo availability on the family suites.