In other words, she's not any of the other characters we see, if anything because the actress playing her does not play any of the other female characters. There was speculation that she was Marion, the most common conclusion is that she is Mandy but she is none of those. We don't know who she is, we never see her face.
Oh, well he tells Bill that it was the same girl, in the billiard room when he confronts him near the end. But it's never clear if he's telling the entire truth.
You yourself admitted you re-watched the movie "but didn't get very far" So now you're trying to pass negative judgement when you never even finished the film, or plot?? SPOILERS* Ziegler said at the end; they did not kill the girl at the party it was set up to look like that to shock Bill into never revealing their secret underworld. She OD'd because she was a junkie, Ziegler said the police found her in her apartment with the door locked from the inside, it could have been the underworld people it could have been her. Either way she was the same girl from the beginning party.
You think you're clever because you've seen the movie several times, yet you couldn't even remember the simple plot after re-watching it, and made an IMDB post needing help..... Right🎓
It's pretty possible that Ziegler's lying. Kubrick showed a jaundiced view of the rich and powerful in Paths Of Glory--i.e., they'll do whatever they want and lie however much they have to.