1a. Gas, lots of it. I ran through about 60 gallons in 6 days after hurricane Wilma. Didn't have any tank losses.
Also, make and store extra RO/DI water before the storm. Water supplies are sometimes disrupted, and after repairing line breaks it's common for utilities to run extra chlorine and/or ammonia to keep the water sanitized. You don't want to be putting that into your tank.
One suggestion I like to give is to take a computer UPS and run an air pump on it. For just 3 or 4 watts, you could throw a few bubblers into the tank and make plenty of flow with some PVC airlifts. Significantly more than a battery powered one, plus, a setup like that could run for days without a recharge.