Nice set of cards there! The biggest "problem" is that they all belong in every
Warg deck, as much as
Wolf-voices and Sharku
As an aside, the first action of Wolf Pen isn't strictly necessary, though it does make things clearer. Veteran Rider seems about right, and the forced cycle in Wolf Pen is very clever.
Did you mean for Feral Unpredictability to read "make an unmounted
warg-rider ..."? Otherwise, this could make Sharku and
Foul Horde damage +2 powerhouses. Either way, a very interesting event!