I've hiked all of the Ozark Highlands Trail, including some of it in the winter, and it's definitely doable. It just depends on the weather. It could be 0 degrees or it could be 70 degrees. It doesn't usually snow a lot, but it can snow, and ice storms are possible.

The creek crossings that I can remember are mostly knee deep or less, unless it has rained a lot very recently. I've only seen some of them once, so I can't say for sure what is normal, but I crossed most of them in March which usually has higher water than December. Hurricane Creek could be higher than knee deep, but it has an alternate route to avoid the crossings. I would not want to do the western crossing of Hurricane Creek in cold weather, because it's really wide and my feet go numb fast. The crossing in Lake Fort Smith State Park could also be questionable, since it is also really wide and has a faster and deeper channel on the west side. Richland Creek or the Buffalo River at the eastern end could also be a problem, but you could start there and have a canoe outfitter take you across the Buffalo in a boat to avoid that.