They were given specific instructions for how they were to be sent to Vri:
Thus for each of the twelve, Sybil will have had to take time to get to know each of them, who they were before being magi, before being forced to flay, and try to find an accord with them before ending their lives. Sybil will track these magi with the help of whoever they wish to join them on their task."You must send them to me with my domains in mind, using proper funerary rites. No mass graves." Vri lightly chided the inquisitor, "Learn about these magi, who they were before they became mages, so that you understand how they've come to what they have. Grieve their deaths properly once you've established a window into their past. But most importantly, love the memory of who they were. Don't pity, but understand they too were once human."
"Then their betrayal of humanity will have come full circle, and they will arrive at my side whole. At least in some measure, the remnants of the souls they've devoured will come to me in their fullness, and we will have reached an accord."
Each victim must be given proper funerary rites. These are open to interpretation, but one would think it'd pertain to the person being laid to rest. Whether it be in a signalist ritual for an Etzori mage, or a ritual burning for an Aukari.