For me, I’ll be using my 90s steel MTB.
I’ve already coated the inside of the frame with anti rust, got a rust resistant chain, and have studded tires at the ready. The studded tires will only go on if there’s persistent icy conditions.
Packed marine grease into my hubs, bb ends, and headset bearings.
On my todo list, I’ll be installing pogies/bar mitts, which have proven to be way better than any glove solution I tried last winter.
I also want to buy/make a mudflap to expend the front fender. This should prevent a considerable amount of grit, salt, melted snow from reaching my shoes, chain, crankset, etc.
As soon as salt goes down, my bike will get more cleaning around critical parts, and a frame wipe down after every ride.
I do have a winter cycling jacket and fleecy cycling pants, but feeling the cold on my body was never an issue last winter. A fleecy buff and helmet liner that gets over my ears are a must, and i may invest in a few extra pairs.
I mean this response isn’t helpful in any way, but as a Canadian who bikes to work, I just use my beater fixed gear. As long as you maintain momentum it works great in up to 4 inches of snow, the fixed gear really seems to help with maintaining balance on ice though. No special modifications, no studs, regular road tires. The comment about layering is right on the money, I usually wear a zip Hoodie and a Jean jacket, both undone to allow for airflow.
I’ve been so tempted to get a single speed bike (not a fixie, though, as i like coasting).
Unfortunately, between the hills and cargo I tend to haul, I do need multiple gears.