I still think Finn's death is due to the influence of, or direct action by, the still hidden third faction/party.
Someone with powerful magical abilities, human or species currently unknown to us, cast a very strong illusion spell on the Damas assassin to help it get close enough to Medb to kill her.
Someone has been tracking Medb and the Alfar and lured them into the city where she would be more vulnerable.
We are still missing far too many pieces of the puzzle to Know that this was Templar action, independent of any third-party influence or manipulation.
This is part of the great storytelling that makes this world so compelling.
It also makes waiting for updates much harder for me as it is so much more than just who the MC's going to bang next and how.
Cheers!!