Lemme get this straight. You stood up Bob's stag night because you didn't have money from being robbed, Joe then threatened you about it because it upset Bob, you told Guy (who has homophobia) who claims that Joe has some issues and has some issues of his own with Bob/Joe, you want to tell Bob about the whole situation and deal with Joe, and all without pissing off either Bob/Joe or Guy. This is all arose because of the stag night.
Just fuck it and do it live and tell Bob/Joe you couldn't go out because you got robbed, have no problem with anything, and it was a misunderstanding and you're not homophobic. Try to gain Bob's forgiveness and don't try to act hostile towards Joe. I'd also take Joe's warning and not 'fuck up their wedding' though I don't understand where he got the idea you wanted to ruin their wedding in the first place. Staying neutral requires a lot of patronizing so do it.
