Zack, thanks very much for finding this info out! I see no reason to believe why Dec. 8 isn't the official date if it's printed in the magazine. Sometimes these things do change at the last minute, but if it was the date given to the magazine, it was the date NBC intends to show it. And as you noted, we should hear it from NBC themselves during Kermit's balloon at the Macy's parade. They always use that opportunity to plug the project of whatever float/balloon is going by...and what better thing for them to plug than the upcoming movie on the same network?
As for the date being "bad," I wouldn't worry, Luke et al. Over here in the States, the entire month of December is FILLED with Christmas programming. (In fact, it usually starts on Thanksgiving!) This is for two reasons: first, there's too much programming to pack into just that last week, and second, the big "event" programming usually isn't super-close to the actual date since most people are on vacation then (thus, lower TV viewership overall). So this isn't unusual or a bad sign. In fact, Dec. 8 sounds just right to me: people are in a Christmasy, present-buying mode, but they haven't been oversaturated with Christmas movies and specials at this point.
On a related note, to answer your other question, Luke: Christmas Day programming usually isn't all that hot over here either. People tend to be celebrating and not watching TV, so numbers are pretty low. So most stations just show sitcom reruns and stuff like that. There are a few exceptions -- TNT inexplicably shows "A Christmas Story" over and over again for 24 hours -- but for the most part, the main Christmas programming happens before the date.
It was also great to read that the Fox show is still in development at this point. It had been so long since we heard anything, I had almost given up hope. Hey, if they're looking for writers, I know someone who just moved out to this area...! ;-)