I live in a hurricane-prone area, and not long ago endured 2 serious hurricanes 3 weeks apart and another less than a year later. Electricity was off for 10 days at a time, communications were severely disrupted, and response by emergency personnel was essentially non-existent.
During those times I saw no difference in my firearm needs. My EDC was still a good firearm for the protection of my family, and since I carried every day anyway, there was basically no change. I see no reason to dedicate any more firearms as emergency firearms, because the ones I anticipate needing are as closely at hand in their normal locations as they would be placed into some sort of emergency kit. My advice is to keep your regular firearms accessible and have a decent supply of ammunition.
FWIW, the most useful things to have are a Coleman stove and fuel and simple non-perishable food stuffs. I carried a gun, but never shot it. I ate three meals a day and drank lots of water. MREs were distributed, and they aren't bad, but if things get bad enough that you can't count on distribution by authorities, you need to be able to get by on your own. Food and water are needed much more acutely than other stuff. After nutrition, bandage materials are important. Minimizing blood loss and keeping wounds clean until you can get professional care is the most pressing medical need. Because of hydration issues, symptomatic anti-diarrhea medications are also important to have available.
And if you ever have to evacuate and not be certain that your house is going to be standing when you get back, you will be amazed at how important your family photos become to you. We keep a plastic bin stored empty so that we can quickly stack our photo albums and throw them in the car as we leave.
