I mean, it was pretty clear. Few chapters ago, it basically said one of the new girls in the mansion is part of this group, and we saw a good colored eye. She is the only gold eyed girl.
Ok thoughts:
Either she was lying to the audience and isn't a transmigrator
Or (and I'm kinda leaning towards this one) since she said she read the story already, she should know what's going to happen. Maybe she impersonated this Fengci person to get a leg up on the plot???