Ok, so I'm looking to go on my first overnight winter trip, to test the waters. Lower Idaho mountains (6000'), 1' of snow, overnight low….15 degrees. Planning on bringing both snowshoes and microspikes b/c not sure what to expect. 3 mile hike in. Trying to not spend a ton of $$$ and trying to extend with using my 3 season gear.
For footwear, I currently have the following two shoes ->

First, a pair of Lowa goretex boots….bought from REI before I discovered UL hiking. I can only comfortably wear a midweight wool sock in these…so I guess these are out.
Second, my 3 season trail shoes….Merrell Mix Masters, mesh trailrunner basically. These fit large during 3 season with just my very thin wool socks. So, if I undo the lacing, I can wear a synthetic black dress sock as a liner, then a plastic bag, then the midweight wool sock, and still have some wiggle room.
So…I need to know how thick a pair of rocky goretex socks are. And….they are $60…so for the first time why don't I just wear a second plastic bag?
I'll then wear a pair of knee high gaiters. For UL purposes, shouldn't I just get MLD ones or I can buy heavier/cheaper ones at sierra trading post to just get me by for a while….
So, with those trailrunners/socks, should I be fine at a low of 15, or would it be better for a low of like 25?