Relocate kitchen cooktop

Moving a cooktop has nothing to do with plumbing (unless there's somehow a faucet attached to it). Moving a gas line is in many cases easier than moving an electric line.

Well, it has to do with plumbing insofar as a plumber is the one who moves the gas line. So long as you are not expanding the footprint of the kitchen in a building that forbids that, moving a gas line is really not a big deal in most cases. Same with moving a fridge or even a sink a bit in either direction. I moved our range across the galley kitchen and it was the least of the issues in the gut reno. Don't sweat this aspect of a reno. There's plenty else that will make you want to rip your limbs off and scream.

my coop would not allow the movement of the gas line. period. check with your building -- not the city at large