Actually i have a completely different base solution as to what i think will happen...
I think Sasuke will have to fight Naruto and they will fight POSSIBLY... then like at the end tobi comes in with his craziness and stuff and what not and then u know stuff happens and they will end up having to work together to defeat him.
All i think the bottomline is that they will have to work together to defeat Madara as for anyone being killed i dont think so other than MADARA!!