I've struggled in ringwraith decks with all of the minions being unique; there's always some site where I want and can afford to play another minion, but the only minion in my hand is a duplicate of one in play.
I would add in at least 2x
Ulaire Attea The Easterling, likely taking out 1 each of Nelya and Otsea to make room. I know Attea is more expensive, but unless you expect to play against choke, the different name is more likely to help than the
is to hurt.
I would prioritize
Bill Ferny SSF over
AVR/Threshold of Shadow. The only downside is he might not work at site 4 (if it's underground) and doesn't do fierce skirmishes, but otherwise he adds 4 strength each time he skirmishes and he sticks around through double-moves. Theme-wise, part of wraiths is that they could travel in spirit form and spread wickedness/distrust in the hearts of men. You can think of Bill as a symptom of the unseen work of wraiths in the lands of men since the last war of the ring.