Just pulled out my 2008 EZip Trailz 3517 miles, and this is its 3rd Winter.
Put my homemade studded tire on the front.
Picked up a used Klondike XT, with still good carbide studs and put it on the back.
Greased the bottom bracket, axles, and motor gear reduction with wheel bearing grease.
Used a "high speed turbine oil" on the freewheels - motor, and 7spd.
I heated them up with a hair drier, till the oil seeped in nicely.
I tried a new "oil" on the chains, a synthetic, specifically designed to repel moisture.
Very thick at 60* room temperature.
After cleaning chain with WD40, I wiped, then "dried" with "low" hair drier setting.
With nice warm chain on bike, I drizzled the thick oil along the chain, while turning the pedal.
Then held a small paintbrush against chain as I continued to turn the pedal, till chain was nicely coated.
I will wipe it down with a rag, after I ride it in, a bit.
Still using the cheapo plastic fenders, better than nothing, I have a spare pair of "full" fenders but they are a hard polycarbonate (plastic), that might shatter from an impact, when cold.
One tip - typically I set my seat for good pedal assist, (tip of toe when stopped.)
During winter conditions, I can drop my seat, so that I can "ski" my feet, for extreme safety.