I don't know that the rule has been explicitly stated in 2e, but in nWoD (before it became CofD), it was explicitly stated as a design philosophy in one of the books (Second Sight, maybe?) that, by default, templates do not stack, and Major Templates always overwrite Minor Templates. Major being Vampire/Changeling/Mage/etc, and Minor being Ghoul/Wolf-Blooded/Fae-Touched, etc.