Unfortunately, I don't think it will. Harry is simply not good enough to be able to defeat Voldemort with magic alone. It's going to involve some random thing to do with love and friendship, possibly the fact that Snape, Pettigrew and Malfoy all in a way owe something to the forgiveness of Harry or Dumbledore, or the fact that Harry, Hermione and Ron have the three different kinds of Ollivander wand cores (dragon heartstring, phoenix feather and unicorn hair), as acknowledged by JKR. Why do you think JKR would bother to begin all these love plots eg. Tonks and Lupin if they weren't going anywhere?
Btw in Book 5 (p108) I think Harry and friends find an unopenable locket in 12 Grimmauld Place, this seems like the Horcrux to me. RAB only said he was going to try to destroy it but remember he wasn't a very good wizard.
My bet is that Harry himself will not find and destroy all the Horcruxes without help (I mean help beyond Ron and Hermione), there will be some reason that people from other Houses need to get involved (eg., perhaps Malfoy for Slytherin's necklace) which may be where the "we have part-allies on Voldemort's side" might pay off for the Order.