For the pancackes, do we need 2 cups of flour, plus 2 cups that go on the other sheet pan, or is it 4 cups for pancakes + 2 cups for the pan?

4+2--it could be written clearer, but the "4 cups + extra for brushing" means 4 cups get mixed with the water in step 1, then the "extra" comes in in step 2--though that's a lot of extra! Also, the dough would be much too wet with only 2 cups of flour