Greetings & Welcome!
As an extreme weather camper myself, I opted for no plumbing to avoid freeze up problems, and lithium batteries are temperature sensitive as well. Solar can be problematic in the winter as well, with shorter & cloudier days. For versatility and much lower cost, I chose a cheap generator & and a battery charger over solar for the rare times my isolator isn’t quite enough.
For heat, I chose an option that doesn’t require power, only fuel. For me, it’s far easier to conserve power usage than it is to create more, plus I don’t want to require power for any of my necessities. Fuel is easier & cheaper to obtain than extra power. My absolute necessities, I can charge while driving if all else fails. I put a lot of thought into being totally self sufficient except for food & supplies, and even then I try to keep a minimum of 30 days worth just to be safe, then as I buy new items I rotate it in and use the older stuff, so everything stays up to date. Canned/dry goods mostly, including meat, and dehydrated things or smoked meats that don’t require refrigeration. I’m munching on smoked New York steak bites as I type this for a late night snack. One of the things I really enjoy about my life is the great food. Friends are always amazed at how well I eat, and the variety of what’s available with a little bit of ingenuity.
"Always avoid complicated solutions to solve simple problems." ~ OffGrid