[Divissima]

For what it's worth:

I think Dumbledore is really dead and won't come back (although his portrait may provide a way for Harry to use him for support) - killing him off means Harry really has to stand on his own two feet and face Voldemort alone in the final showdown

If one of the three dies, my money would be on Harry - his fate is so intertwined with Voldemort that it would not surprise me if they both have to die (as hinted at, I think, in one of the previous books - I'll have to refresh my memory) - Harry may be a horcrux and may have to die in order for Voldemort to die

It would not surprise me if Snape really is evil and has been working as a double agent - I think Harry may have to do battle with Snape (and win) before the final showdown

The ewoks will prove decisive to the final battle and will help destroy the ring of power