Lube-wise, I highly recommend winter-weight chainsaw oil. Very thin, doesn't get all over everything. It's also good for the insides of 3-speed hubs such as Sachs and Sturmey-Archer.

Btw, for my first winter-specific bike I built an old Sturmey 3-speed into a modern rim and it worked great. I set the gearing up so that 3rd (highest) was for cruising, 2nd was for cruising in slush, 1st was for towing the trailer through slush. (I did not need a higher gear, as how often do you need to pedal going downhill in winter?). The new Sturmey 3-speed hubs are better than the old ones because they do not have the dreaded neutral (freewheeling) spot between 2nd and 3rd. Some also have either drum or coaster brake. I had mine set up with a little housing as possible (one little piece at the front) and it always shifted, even at -25C. I eventually replaced that set-up with a Shimano 7-speed Nexus hub, because the three speeds ended up not being enough for trailer-towing in winter.