After just typing all my thoughts, something went wrong and its gone
So second try.
Some has been said but here goes.
1. Already mentioned but weather and notably wind. Proposed camping spots may need to be changed depending on the conditions, as 4 season or not, a tent will not withstand winds that are ripping lumps off trees and roofs from houses, they are all just canvas. Whilst you will be able to gain the latest reports on weather and snow conditions, you probably won't once you're out in the wilds, so be prepared to change, have emergency routes/ideas to hand and take account of these regarding letting others know to avoid a call out unnecessarily.
2. As above re snow conditions, but also allow much more time for walking in soft deep snow, as opposed to hard stuff, although walking in crampons can be arduous depending on how use to it you are. Ability to brake with an ice axe is essential. Further to the snow conditions and the fact you won't be able to access updated information, it is worth understanding how to assess the snow while you are out, the knowledge to dig a snow pit to assess it may be useful. I've used it on several occasions, the results of which caused me to turn back, one certainly being the right decision given the amount of avalanche activity witness walking out, which was not there on the way in.
3. Not mentioned GPS, but it would be useful for plotting key points on your route, as not least it can be much easier to follow than map/compass if conditions turn bad, also useful for plotting locations of Bothies and/or shelters. Carry a spare compass.
4. Carry a bivvy bag, even the plastic ones that you can fully immerse in, as this could be a life saver in serious windchill. Also look into the techniques for a snow shelter such as a snow coffin, again to remove yourself from the windchill. A snow hole would take too much time, that could be better spent on removing yourself to lower ground.
5. I'm assuming you will be self sufficient for meals, hot meals, as the only thing keeping you warm in a sleeping bag is you. Worth carrying a flask of hot drink too.
6. For fear of stating the obvious, and asuming you will have the relevant clothing, winter mittens, windproof will be essential, and also snow goggles, balaclava, insulated layers etc.
If anything else springs to mind I'll add it in, but otherwise only you know your capabilities/experience, most of all enjoy it safely