Christmas at Disney is such a fun experience! It's great that your children are into it.
Here's a great idea from the past. It's a little trickier now, but still fun.
Set a dollar limit (say $5 per) and visit each country in the world showcase. Purchase something within those limits and fill their stockings. It's a GREAT way to enjoy Christmas morning, especially if you have them guess which country each little giftie came from.
We are going to be doing it again this year. (You do know we're going to Disney for Christmas too, yes)?