I am super impressed you are attempting something so bold. I've been teaching winter camping for NOLS for over a decade, and my experience is decidedly NON lightweight!
My record low temp is 40 below zero (a tidy number in C or F) under a tarp.
But - I think this is an area that needs to be tackled as the next big challenge in this weird little sub-world of UL nerds.
Right on for you!
I have a set of FF booties, and they have two pars, an INNER and an outer. The INNER is easy to sleep with on my feet. The outer is a thin fabric "shell" and has a foam pad. I've found it's hard to sleep with true booties, something about the foam pad makes my feet sorta sweaty, and they end up chilly.
These are really helpful.
So, you are going with liners only. To me, that seems bold. The few little excursions I have done in the winter with "Trail Runner" type shoes worked out well.
I wore slightly larger shoes, and used a pair of NEOPRENE socks, and that's all. (gaiters too, no over bootie). It was a nice system. In retrospect, I would use a thin plastic bag as a VB inside the NEOPRENE sock as a way to keep em a little bit drier. It was brutal putting them on the next morning.
Just pull a pair out of another pair of sneakers, Nothing fancy. If your shoes get wet (they will) changing the foot beds will help your feet feel a smidge warmer.
Also, stack 'em inside the booties, conduction is the way you'll loose heat.
Can you hike in the tyvec booties? Or are they only for the snow shoes?
4.25 OUNCE CRAMPONS.
These are just like, little creeper things, right?
Don't take HOT-packs for your hands. Take the right glove system instead. I would rather have an extra dry pair of pile mittens than a hot-pack.
I take a lot of gloves (mostly liners) when I'm out in the winter. I don't use mittens. But, i do ski trips and deal with a lot of snow, and I dig a lot.
You said "one may freeze" - - - Hey, if you are going as light and bold as you say you are, don't your DARE let yourself pull a green-horn gumby move like letting your water freeze. That's totally INEXCUSABLE!
If you are gunnna use wood, make sure to take something to start the fire. If it's wet (like raining!) you'll be happy to have it. Esbits are good, but a tiny squirt bottle of denatured alcohol would help too.
Don't take a thermos!