I posted a thread and it disappeared. So here goes again! My theories are
Percy is "spying" on the ministry on behalf of the Order, Dumbeldore wasn't happy with the way things were being run remember, they sacked him a headmaster of Hogwarts didn't they. Percy will report all back to the Order, which will help in the battle against the death eaters.
Draco will need help from harry. Voldemort will threaten Draco's mother in some way (remember in Half Blood Prince how owrried she was about him). I think his mother is the only person, other than himself, who he loves. Harry will help him and then Draco will be indebted to harry!
Hopefully Luscious won't get killed I like him(think it's the Barbie wig that does it)
Neville will turn out to be a star, and will kill Bellatrix - in fact it hink he may use the cruciatos curse on her a few times first.
I can't make up my mind who dies - I have a feeling it may be Lupin, leaving Harry virtually on his own without much adult support. Or it could be Snape as he redeems himself, can't get my head round him being good though!