If you're prepared, and they are, it's fine. I've camped at even colder. The preparation is key, though
Never underestimate the ability of seemingly smart kids to prepare like they are idiots. I suggestions to help with the prep, if you like.
Having said all that, winter camping is not my favorite. I will do it as a way of teaching young men the needed skills, and to have them use those skills, but generally it's a lot of standing around in the cold until you go into the tent.
On the other hand, we had a ward member loan us 4 snowmobiles once that we used to take the boys into a backcountry snow campout. That was pretty awesome.