NamikazeNaruto would be my vote specifically for Assassins. I'd nominate Waka, but he has not been active for a while.
Wakalord (Eatenbydistance) is currently active. He gets my vote for PVP rep.
Since there are only going to be two representatives who will alternate in collectively representing shadows+assassins, I think one rep should be PVP focused while the other is PVE centric. In that case I'd go with:
PVE- Kitru (shadow)
PVP - Eatenbydistance (assassin)