The problem is there are 2 categories. Microwave safe just means it won’t explode, or throw sparks. The other type sorely lacks a name still. It’s the stuff that is transparent to microwaves and so won’t heat up at all, except for heat transfer from the food.
In fairness, the only thing many people will lack is water. It’s not an exclusive stash, but in addition to what’s in your cupboards.
You can get 10L or 25L quite cheaply. 1 should do per person, maybe with an extra for cooking. Or just grab some big bottles of water.
A hand cranked flashlight, candles and lighter are all a must anyhow, for a power cut. It might also be worth having a cheap camping stove tucked away.
Food wise. It’s just a big bag of pasta or rice, along with some cans/jars to make it pleasant to eat. Throw in some hiking snack bars and you’re sorted.