The Rangers used to decide who goes or not based on the equipment and the credibility of the individuals involved. Now, with the new rules I am not certain how strict they are, but I am sure they would turn back an obvious novice. How cold? Last year on Mt. Washington summit in January we experienced a high temperature of negative 7 degrees with 23 mph sustained winds bringing the wind chill to about 30 below which is probably average/tame for that peak. Good thing it was sunny cause I wouldn't have made it up there otherwise. And as others have said, Katahdin is a whole nother monster due to the remoteness of the area with Mt. Washington-like conditions/unpredictability. Anybody who goes up there better be damn prepared with some solid experience cause it's a real mountain.
The chimney notch would be the technical crux of the route. I would probably bring a couple of ice screws given they are so lightweight as well as a few cams/nuts & a 30 meter rope along with a general mountaineering axe. The other possible crux which I would consider more prominent would be getting some weather while traversing the knife edge.
I hope to do it this winter but the time necessary for me to take off along with getting people to commit & getting a lucky break with weather makes the challenge as tough as the climb itself!
Ralph