So Ron and Hermione, both being of age, resolve to go with Harry on his last mission so to speak. What are the roles that they will play? How can they help him on his mission to destroy Voldemort?
Hermione's part will take over what Dumbledore did for Harry. She will be the big thinker. I think that Ron will fill the Sirius gap. Sirius gave Harry the backup to go on his own instincts and be brave and bold.
I think ron may offer his life so harry can advance to one of the Horcruxes, like in the Chaber od secrets, he sacrificed himself in the chess game so that they would win, and harry and Hermione could go on
When it comes down to it though, Harry will be the one who does it. They are there to guide, but I think the final showdown will be Harry and Voldemort alone.
..without the deatheaters around? do you think Voldemort will want want to fight Harry without his Deatheaters around? if Harry did win that would be a big indication if Harry was going to die after defeating Voldemort.