After re-reading the proposal, I would have to add my assent that there be unique poses for each WW. Although I might take it a smidge further.
With these being large-bodied creatures (40mm or a 50mmx75mm base) I think that the possibility exists to try something a bit different. It's quite common now-a-days for creatures of about that size to be made from left and right halves...like the way the horses have been made. I don't think it would work for the entire set, but would make an excellent way to provide variation (and keep in line with the reference). Say, perhaps three L & R torsos to mix and match into nine basic "galloping" poses.
From that point, you (well, OK, "I") would want to be able to make some standing poses to give a bit more diversity and be able to single out a few models as more likely candidates for Alpha-status. I'm not entirely sure how that could work. You could use the more conventional torso/legs division, or you experiment with a more modern front-half/back-half (or similar variation).
A fair number of different heads will also be necessary (at least four, six would be better). It's easy to think that just one or two will be necessary, but I'd really like to see more. One to look like it's baying (only one per box--two at the most, it's an easy thing to over-do), others with their ears up or back (maybe one up and one to the side), and maybe two heads with their tongue lolling (one to each side).
I wonder if the heads couldn't be done left-side/right-side as well, and if that would be an improvement or a huge PITA. The baying head would only fit together one way, and it would be weird to have heads with the tongue lolling out both sides of the mouth. Maybe a way to do the top and back of the head with the lower jaw as its own piece? I've got too many ideas on how to handle that--and no way of telling if any of them would work.
And for more inspiration, I always recommend Ron Spencer's werewolf art.