1) Nonnamed NPC (they are fae, yes) are killable in general, but it's prohibitively difficult for most average, normal humans. Vampires have an easier time of it, yes, but- There's less of them so it's easier to get busted for killin' a guy if the corpse has a couple suspiciously teeth like puncture wounds in his neck. If your character does get caught for a murder, they'll wind up in fae jail for a month.

2) PCs are not aware (named, Royal) NPCs are entirely unkillable and must learn that on their own from either talking to other Adopted or learning from experience.