Sorry, but ANYTHING that is put in the game is canon. A good writer makes sure it NEVER contradicts itself. You do not get a remake unless you can put it in the story. Square is usually good at it. But sometimes they make mistakes, just as everyone else.

The only exception are the minstrel ballads that are supposed to be exaggerations of what you did by the minstrel. And that's because the minstrel doing exaggerations is on itself canon.