He had horns and fangs. Surely you understand by now that it's only killing *humans* that's wrong and unacceptable.
As for the party - the cop is Officer Modini, a woman Diana rescued early in WML's run who had to overcome some cape-related bitterness. She was a brunette the first time we met her, but Diana seems to have some kind of redhead-inducing tertiary power over women. The other woman I can't identify - I'd almost say it's Quinn with her hair grown out, but we see her again later and she's still got short-cropped, so I dunno. She was with Etta when they rescued Diana and Donna from the underground river, though, so apparently WML thinks she's somebody relelvant.