Adam, you shouldn’t worry about the death ward/half-orc racial because you have already said that you would allow Berg to use his feat to attack in both instances. You said it when Death Ward was first casted on Berg in the arena fight against the big mutated orc. You could of course have changed your mind.
A thing that had me puzzled was the fact that Berg took full damage when he got hit with necrotic damage. Unless you have changed his ability as a totem barbarian he takes half damage from all damage except psychic (page 50 PHB)