You forgot the "private theologian" clause, but it is impossible for RCs to know with certainty which level of the magisterium every teaching fall under, and even the CCC may contain errors.
Slowly, I get the impression that "cannot err" claims of infallibility are things that only exist retroactively within the Catholic church. I'm hearing that Cardinals can elect the "wrong man", that Cardinals can resist the Holy Spirit, and that Popes can make statements in opposition to doctrine and dogma which have to be corrected or reinterpreted later. Where does infallibility take place, if not "after the fact" with the victors writing the history books?