I could see Madara transferring himself to the Hashirama body he was growing, perhaps also transferring the missing Rinnegan that Obito didn't transplant. Perhaps while Obito is weak/immobile, a Zetsu will emerge and "yoink!" steal his current Rinnegan, thus allowing Zetsu-Madara to have both eyes.
Originally Posted by Pure Logic
No, the "Advanced Zetsu Clone of Madara" theories are NOT phased-out in a Post-Tobito fandom.