I think what's stopping me from being able to help out is I'm struggling to understand how the "Mastermind" code works, and I really think that's the key to figuring out what we need and what we can "discard". I've just looked up 3 different sets of rules to the Mastermind game, and even using the logic Dawlthy put in his original post I can't seem to get the same answer he did with any of the rule variations. That's probably me being stupid, though.
Can anyone further explain how it works?