I wouldn't hold my breath.
Back in January, months before the current sequence of train wrecks started landing on us, there were signs that hats had overstayed their welcome, so to speak. We basically have been rehashing the same thing every year for a while now, the concept is growing old, and ideas for new, interesting hats have grown scarce.
In addition, traditionally the whole hats challenge has implied increasing participation on the sites, particularly in moderation activities. I think I'm not spoiling anyone when I say that many users are currently in quite the opposite mood here.
And last, but not least, Stack Exchange going festive again as if nothing was happening would not strike me as the right move to make. At best, it could appear as them handwaving the current situation and trying to get back to business as usual. At worst, it could appear as them taking us for dumb goldfish that will happily line up to contribute to the sites again as soon as they add a little gamification.
I think that ship has sailed. Really.