Re:Can we discuss what role we are?
I guess you could announce what role you chose, and what roles you passed on, but it seems to me that it would go against the whole "bluffing" mechanism of the game.
If you were playing poker, you could easily say "Oh, I have two Jacks and an Ace." You might be telling the truth, you might not. (I'm pretty sure they frown about this kind of out-loud bluffing in poker..) The same could go for announcing the roles you choose in Citadels.
Overall, I think it's better just to keep quiet about what role you choose and what you pass on to the next player.. In the end, you would only be (possibly) providing more information to the other players, and thereby probably just hurting yourself. But if everyone in your group agrees on it, you can play however you like.