Well i think i can explain that. Edo tensei brings back the corpses to life and it only took chakra from Kabuto when summoning. Beside that he's using chakra to control them in battle, but he doesn't need to take control of the jinchuuriki anymore, so that doesn't matter. Then madara uses the same technique as Nagato, he doen's need chakra feeders cause these corpses doesn't need chakra, cause of Edo tensei. So the only thing left to do is control them. And i gues he's doing that with the rinnegan/sharingan.
@above me. Yes cause nagato had only rinnegan, but tobi has a rinnegan and a sharingan, so it propably takes over the eyes of the user.