Union or league is not really the question.* The real question is what position did they play? Macbeth's a hunky warrior to start, but turns out to be a bit of a flash in the pan, with power going to his head. Sounds like a centre to me. Macduff, slogger, slow to start, but makes it in the end? Classic prop behaviour. Julius Caesar, live fast, die young? Must be a winger. This is definitely my new favourite game. Along with the 'what would any given Shakespeare character be listening to on his iPod?' game.
* Because of course, the answer's union. No-one has ever seen the Aire Valley FM dancing girls in a Shakespeare play, and it's not a rugby league match without dancing girls in jewel coloured lycra and furry yeti boots.