Tradition is that which is handed on either by word of mouth or written down. The Gospels and the rest of Scripture is in fact Tradition written down as is all dogma and doctrine these days. Phrases such as “the living Tradition” are meaningless only serving to preclude explanation of what is meant by them. The same with “the movie is still running”; it sounds quite profound but what does it actually mean? You may have an idea in your head but does anyone else have the same idea?
The Catechism is not for ordinary folk to learn by rote like the Penny Catechism, it is a teaching document for teachers of the Faith, primarily the bishops. Insofar as it repeats Scripture and the infallible decrees of popes and councils throughout the Church’s history it enjoys the same status.