Madara must also be the mastermind behind making Itachi kill off the clan.

My theory is that Itachi wants Sasuke to become strong enough to defeat Madara because Itachi can't. But to defeat Madara, he must be able to defeat Itachi. Though I think something will spark and Madara tries to kill Sasuke and Itachi takes the hit for Sasuke and Itachi dies.

And then Naruto will fight Pain.... 1v1 maybe?

Others will probably be occupied.