Most important: oxygen. My tank survived 178 hours at 66.1 degrees, and the hardier fish and all corals lived. I had no pump, no heat. But the 66.1 was critical, and I oxygenated it by hand (pouring total tank volume) every four hours for days. THe lower temperature actually HELPED the fish and corals survive---because they use more oxygen at higher temperatures and the water at higher temperatures can carry less. That's worth knowing.
HOWEVER---you should just outright get a generator---one of the smaller, less expensive portables would suffice for the tank. If funds are too tight, at least get a propane indoor-capable (with ventilation) stove for heat, a good lamp, and a gallon pitcher.
HOWEVER---you should just outright get a generator---one of the smaller, less expensive portables would suffice for the tank. If funds are too tight, at least get a propane indoor-capable (with ventilation) stove for heat, a good lamp, and a gallon pitcher.