I live in the middle of nowhere so I have a generator. I also bought 2 inexpensive 'live bait' air pumps that they make for fishing that run on 2 D batteries for like $17.00/each. One for the main tank and one for the sump. They say they will run 24 hrs per 2 batteries but I haven't had to use them (yet). I test ran them for 8 hrs, with lights out and no other aeriation in the tank and everything seemed okay. Of course, I only have maybe 25gallon total water volume so that idea might not work for a larger system, or you'd need more than two pumps. Stocked up on spare patteries too.
As far as heating goes, I've got 4 or 5 plastic quart milk bottles all clean and ready. If it comes down to it, I can fill those up with hot water and float them in the tank. Even if the generator isn't on, I still have propane so the stove will work to heat up water.
This winter is shaping up to be a peach, isn't it? I saw on the news another winter storm blowing in starting Monday night.