Wow, thank you! *snaps off chunk of rich milk chocolate and offers* I'm glad the ending worked for you as it went through numerous changes whilst in outline form.
The way I view the prophecy (completely ignoring the issue of whether a prophecy must come true) is that either must die by the hand of the other...and once the 2nd Harry is dead, Voldemort is free game as if there had never been a prophecy. So I think Snape's chances look pretty good.
Not to mention the fact that Harry doesn't even die directly at Voldemort's hand so the prophecy may have even less credence in this world.