There was a female KO admiral in Broken Realms, they should give her a model
Love me some Skaven but not a huge fan of the brood mother concept, got to get those numbers from somewhere though
With the necroquake gone and Alarielle talking about life hitting back (paraphrasing heavily) the concept of wandering/endless spell style monsters doesn't seem so far fetched, lack of rumours aside.
I never got to play with old Ghur realm rules (plus had no monsters to use anyway) but wouldn't hate the idea of some fauna to fight on the battlefield as well as your foe