Well here's the thing Edo Tensai Kakashi would be one of the toughest opponents out there. 1000 jutsu and in Edo form, he has the means to use all of them an unlimited amount of time along with Kamui.
But the only way either would win is through sealing jutsu. No doubt Boss shinobi like them have it but ya know xd we need to see what a mug can do but Madara looks like the better shinobi in the case still. However Kakashi is like a switch army knife, has something for everything.