And despite all of that, Nagato was still unable to walk.Physical limitations exist only because of some kind of defect with the body or because something in the body is being overtaxed in someway. Edo Tensei do not possess the conventional human body. No organs at all.
-Itachi has no sickness when an Edo Tensei.
-Itachi was able to act in White Rage and use Susanoo despite Sasuke w/ a living body being unable to do so.
Susanoo causes pain, and it has something to do with the cells. Itachi against White Rage shows that he either doesn't feel anywhere close to the same amount of pain the human body feels, or that he doesn't feel pain at all. Edo Tensei don't have cells either.
I agree that using Ribcage w/ a clone isn't the key to victory, it's just the key to countering Genjutsu.
Itachi does feel pain. He squinted, held his ears, and couldn't move, just like Sasuke. Sasuke not being able to maintain Susanoo only means Itachis focus and chakra control is better than his.
How exactly do you think Itachi wins this? I'm curious.