Well the Alliance forces would likely be on alert, no matter if he has his eyes upon reincarnation or not considering the fact that he was Uchiha Madara's little bro. Izuna seemed to be highly distrustful of anything Senju-related, customary of that time's Uchiha, and he´d likely just try and cheer for his big bro to wipe out everything the Senju stood for. Madara however, would probably like Sasuke enter a somewhat vulnerable emotional state but with the way those two are the likelyhood of Madara changing is below 10%.