I wondered how Lottie knew about Dean as she didn’t meet him during her visit, but the more I think about it the more it makes sense. Dean isn’t exactly a subtle person and Lottie and Esther talk recently. If he came up during their vampire adventure or in modern day in text, things would click. And similarly Lottie is likely smart enough to never speak her friends name. Which given her lack of tact says a lot .