Our wedding is at 10 a.m., and we ended up making a 2 p.m. reservation at Whispering Canyon Cafe at the Wilderness Lodge. We have a full house for our Intimate wedding, and we are asking a few extra people for the luncheon, so we have about 25 people coming to the lunch. We actually don't have that many kids, but it was one of the few places we could find that was affordable, had a menu we thought would be agreeable to everyone (a lot of the family wouldn't go for things that are "too fancy"), and could accomodate the number of people we were bringing. With that number of people, you are usually looking at needing to rent out a room.
WCC is definitely very kid-friendly. For a large group like we are bringing, you have to do the skillet, which is a one-price meal. It's bascially a barbeque-style meal: ribs, corn, etc. You can look up the exact menus on-line. The lunch menu is a little cheaper than the dinner menu, but the dinner skillet had a little more variety, and we liked it a little better, so we asked, and they agreed to let us have the dinner skillet at lunchtime.
Good luck! I know we had a tough time figuring this one out!