Add me to the group!

I snagged a FD discount this morning for our trip in December, but I need to do some more math. Maybe you guys have some thoughts/input on what to do.
My family of four will be going to Disney World in December for 8 nights, but then only my husband and I will be returning in January for the half marathon for a stay of 3 nights. We are thinking about becoming an AP holder and the questions wont stop in my head lol. Any thoughts on what to do? I am pretty sure we would be returning again as a family of four in late 2018, so it would make sense to become an AP holder. How does FD play into that? Tables of wonderland?
My kids are 6 and 3 and we stay at Art of Animation because of the family suit set up. I am sure we will continue to stay there until they are a little bit older.
What would you guys do? All thoughts/input is welcome! Thank you friends!