The chemicals in fixer are also used in fertilizer and swimming pools.
Most of the film developing equipment in the world is made out of metal - primarily stainless steel I would think..
If the pots and pans were stainless steel, go get them out of the garbage and just clean them reasonably thoroughly.
If they are something like an old, highly seasoned cast iron frying pan, I'd be worried about getting fixer into the seasoning, but otherwise that pan should also be fine if thoroughly cleaned (and re-seasoned, of course).
Teflon or other non-stick coatings - who knows?
If you are going to use your kitchen - I do - just know that you need to set it up to make cleaning up afterwards easy. Leaving food preparation stuff around while you work there makes that really difficult.
Ingesting black and white film development or paper development chemicals is not a very good idea. But those chemicals are of similar toxicity as a lot of household chemicals, including many that are used to clean kitchens.
I would be a lot more worried about spilling dishwasher detergent on my pots and pans than I would about spilling fixer on my pots and pans.