We have a gas BBQ that has proven itself in snow already (our mad neighbours and ourselves, 5 households, drag them out if the green is covered in snow for a BBQ and hot wine while supervising the various DCs and just catching up and being sociable). We cook all sorts on the BBQ anyway over the flames, on skewers, in tin foil packs etc.
I have a Kelly kettle too - just find a few sticks or pine cones in the garden/on the green/in the local park/buy kindling sticks and that works well for hot water and for cooking (I tend to use camping type pots as they don't need so much heat to work).
And a 1 ring gas camping stove - we keep that and the gas cannisters at home while the rest of the camping gear goes to a storage unit for winter, just in case.
All these 3 need to be done outdoors - but as long as you have decent clothing (suitable warm and/or waterproof), then that is ok. And depending on what you are doing, you don't need to be there the whole time (a slow BBQ joint and maybe a larger pot of water to make best use of the heat could work away fine for ages just being checked periodically). Hot water is enough to make lots of things work in an emergency (cuppa soups, couscous, easicook noodles, microwavable rice/pasta packets, fresh pasta, frozen petits pois peas (especially if you let them thaw first), smash, ....).
In terms of cooking indoors.
I don't think the gas hob would work without electricity (there;s a safety mechanism in it - but I could be wrong). I know the electric oven does work without gas, as we've had the gas off before and I could still oven cook dinner.
Microwave if the gas was off, and electric kettle is useful too.
If I had to get really creative, I would probably look at putting tea lights on the gas hob (leaving gas turned off) and a camping pot or an oven tray over that on the hob support bars as a slow fry-type option. I used to have a thing to keep dishes warm on the table using tealights that could work to at least heat things, but I gave that away a few years ago as we never used it - but dishes would start to bubble and boil on that!
Or maybe putting some tinfoil wrapped food, like potatoes to bake, into the wood burning stove. It's a closed stove, but backed into the fireplace, so we can't put a kettle or pot on top (MIL has one that you can do that, in her kitchen, which works ok for stew-type meals and to heat a large old-fashioned kettle).
And I know we've "cooked" marshmallows in a HM solar oven before, so the sunny south facing windowsill could be put to some practical use, if the sunshine cooperated and we were home in daylight.
It's possible to do. It needs thinking about. Food may need to be cut much smaller than usual to cook faster (well, cook using less heat energy than usual), and certain things may not be possible.
I do that thing with the headtorch and a full plastic container of water as a lantern in our tent when camping. DH was amazed when we had a power cut and I did it at home.
We also have plenty of candles and tealights (and safe containers to have them lighting), as both of us grew up with regular power cuts in the 70s/80s in rural areas. Usually just used for ambiance, but I never let the stocks run down so that we don't have emergency supplies.