Itachi and Sasuke will manage to *Defeat* - not kill - Kabuto - and then trick/use Genjutsu on him to make him end the Edo & making Itachi redie. Sasuke will then have to fight a weakened Kabuto and kill him/Sasuke will kill Kabuto while he is under Genjutsu. (once Kabuto dies, the Edo Tensei Cannot be stopped!)
Naruto and Sasuke will fight once Tobi has been defeated (there are many theories to state that as Sasuke is actually a genious - (he knew he couldn't defeat Tobi by himself/ with his current powers - and exploited Tobi) - Sasuke and Naruto MAY fight Tobi together and then have to fight eachother to end the feud of the older and younger sons of the Sage of 6 Paths (Uchiha - Sasuke, Senju (Uzumaki) - Naruto)
The Masked man (Tobi) will most likely be someone who we have heard of / seen during the series - who wouldn't feel trolled finding out that Tobi is some random we've never ever heard mentioned. This may mean that Tobi is the SO6P's Older Son, it could be Izuna, Hell the OBITO/TOBI theorists might have it right, there's really no telling until its been revealed as there are much too many possibilities.
Also, hopefully Tsunade will no longer be able to maintain her duties as Hokage - from either death or mortal wounding - and Naruto will be named the next Hokage!!!!
My 2 cents