Ābra Cersei Lannister issa daor.
Cersei ñuha dāria issa.
She loved them for a while.
*iksos daor. I think the negative requires the verb to be in the subjunctive. Like in "zaldrīzes buzdari iksos daor" (a dragon is not a slave).
Priests or priestesses? If the root can mean either, how is gender determined?
In one of the first episodes of the seventh season of the show, they explain that at least some High Valyrian professional nouns are gender-neutral, like the words "doctor" or "lawyer" in English. That's likely the case here.
It could be either. Or both. If you absolutely needed to specify the sex of the priests, there are ways to do that, but I'm not sure whatis idiomatic. You'd have to ask dedalvs.