It wouldnt necessarily be an awful idea because other than being female characters with no real powers, there are no similarities in their situations.

Elektra span out of a movie that wasnt exactly popular in the first place, and Catwoman wasnt actually a spin off of anything being that it was years after Batman Returns, and the Catwoman of that series and the solo movie have no common ground other than the name. (Different actress, different costume, had super powers, was given an origin that had no connection to the previous one etc etc etc). Saying Catwoman is a spin off of the Batman films is pretty much like saying that Batman begins is a sequel to Batman & Robin.

Snarf is shit. His death will be rejoiced!