I thin there's a possibility that one of the trio will die, but at the same time, it almost wouldn't be fair. Harry's obviously the lead character, but Ron and Hermione are practically family. Their like the new murader group or something.

About the whole couple thing, I think Harry and Ginny are going to knit together close as things get dangerous. I think Harry and Luna's friendship will get stronger, but I don't think the two will fall for each other.