In this legion mission for task 1 where you have to use the artifact on 10 Roathirs. In Hostile Takeover, they are rare NPC's. In this mission though, does their rarity switch to uncommon or do you really have to find 10 rare NPC's?

not sure but they're not hard to find, if you really want you can find all 10 within an hour. Most the times i find all 10 before 500 npc kills, so not really that 'rare'.

Okay. I am thinking then that they are "rare" in the Hostile path, and then "uncommon" in the Diplomatic path.