Hi, Tara! What a fantastic time to head to Walt Disney World. The parks and resorts will be getting geared up for the Christmas holidays, and I can't help but feel all jolly and festive with all the decorations and holiday events.
The best way to keep track of whether or not an special like free dining will be offered during your stay, aside from checking right back here with the Disney Parks Moms Panel, would be the
Walt Disney World Special Offers section of the website. It lists current offers and what the criteria would be to book the deals.
Disney Dining Plans can be added to a
Magic Your Way vacation package. If there is a free dining offer, instead of it being added to an existing reservation, you just need to call in or talk to your travel agent about changing your reservation to a package that includes the free dining offer. Rooms for this offer are limited, so as soon as you see it as an option, you'll want to get right on the phone to 407-939-1936 to make the change.
I'll keep my fingers crossed that you luck into an offer that works for your family! In the mean time, thanks so much for your question, and happy planning!