The long range forecasts aren't calling for cold here, so it doesn't look like you will face serious cold. I have never been in the mountains at -20, but -5 and -10 are cold and scary enough. You hopefully will avoid that, but with that said it is always cold on the summit ridges. We get snow tonight, and there is a possibility of substantial snow on Sun/Mon. There is 24" at the stake on mansfield, so while I haven't been up there, my guess is that currently the trails will be navigable and packed as of today. that could change if we get lots of snow. But the depths aren't going to be so deep as to obscure the white blazes and trail signs. So I think you could hopefully find the LT along there on the south side of Butler. I would bring the tails if you are doing that section of the LT (taylor to butler).
As to gear, I worry that the houdini is inadequate and doesn't have a substantial enough hood. If the temps are warm, you could probably manage. But I find a heavier more substantial shell, hard or soft, is necessary in the winter, warmer and more protective. And a hood that can go up to the nose is key. But you seem to be carrying several balaclavas and a buff, so maybe those can substitute. But if you face brutal conditions near and above treeline, I worry that the lack of full hood and a real shell is going to be a problem. You could always wear the down parka I suppose. I am tempted to say the forecast is warm enough that this may not be a concern, but we ski at Bolton and even on "warm" days in Vt in the middle of the winter, the summits are still very cold usually.
I would carry 4 handwarmers, so you could use two and keep two for emergencies. I can't quite figure out your glove system. Light fleece gloves are not warm enough most of the time once you are high, and you don't have a shell glove or mitt. Maybe you can wear the timberlines and keep the fleece and the mitts as backups.
For emergency gear, I would carry a bivy of some sort, they are really light. You can't expect to dig in the snow, since you may be exposed on windswept ridges. The shelters are likely to have a candle left there, but I would think about bringing one for the long dark night. You don't need avy gear, and you should be able to reasonably expect your cell to work; the tower is on top of the Mt.