In fact, I think it would be a great idea if each of the confessions were to begin a series to reveal their beliefs to the Lurkers: "Catholic beliefs on x [Catholic Caucus]".
As long as no other confession is mentioned, e.g. as a comparison, there is no reason the thread should opened for challenges or ridicule.
How does one talk about one's conversion then from Protestantism to the Catholic Faith without any reference to doctrine? How does one say "After much study, I was convinced the X-doctrine is in error and so I came to believe as the Church teaches." Would that then be seen as a polemic attack?