I always had the feeling that Gai and Bee will die in the war. Gai to pass the mantle to Lee adn to show the power of 8 gates and Bee had to die for Juubi's completion, making Naruto the last living Jink. Also I think Tsunade will die soon in exchange of the Kage's survival.
Gai's death will be epic; seriously even a shitty author would handle such death decently from its own hype; it would suck if Kisahi manages to screw it over; so it would probably be epic.
I don't think Lee die; though it might happen.
Tsunade's SHOULD be. She is obviously the one who kishi is gonna kill ;-;. Also she is the hokage every other known hokage had a decent death, sure she saved the kage but an off panel death for your hokage/sannin/strongest kunoichi better not happen.