So, I am requesting an addment to the 'Traveller Magic' section. In The Devil Inside, Nadia used this magic to call forth Katherine in Elena's body, and so on, it would be possible for a vampire to perform this kind of magic, at least to some degree. In the same episode, Nadia needed Mia to do the ritual for Katherine, making people assume, that she cannot do so.
For 'Sacrificial Magic', you could add a statement like "It seems, that practitioners of Sacrificial Magic, specialize in channeling.", as Papa Tunde was shown to do.