You know, secretsolitaire and I were discussing "Cross Reference" in the context of the great reunion fictions you mention here only a couple of days ago, on her LJ. I have to agree: for me what clinches it, for all of them, is precisely the B/J friendship.
Brian going after Justin is, of course, a bonus. But I like how in these stories, including "Cross Reference", it happens organically and it's not a huge, theatrical gesture, just the courage to finally acknowledge what's obvious and inevitable: saying "I love you", stopping Justin from going, admitting that it matters, etc.