So I think that just leaves Violet to show up right?

As far as I read into the backstory, she's been staying indoors, but she wasn't on the news report. Did she attend the Gala as a guest or did she just happen to walk by?

It seems like she isn't being actively searched for. I was just wondering for plot reasons, maybe she could do stuff like scouting, since she's not being looked for. Bring up less suspicion