Incidentally, I said I don't want to nerf atlanteans; but changing a bit their starting resources would not really be a nerf.
So far, one of the latest discovered advantages of atlanteans is that they can get a full trained soldier (minus defence, but those promotions are weak enough that you can skip them) in 30 minutes. this happens because they already have all the iron and coal they need from the start, and they only need a gold mine to extract two pieces of gold.
I think removing 3 coals from atlantean starting inventory would be enough to force them to make a coal mine, slowing down a bit that strategy. To keep things fair, we could give them a bit more bread and fish, enough to extract that coal once the mine is done.
or maybe we could remove 3 iron and swap them with 3 iron ore, essentially getting the same effect, and again compensating with something else.