I'm not always sure of everything that's happening; and I've certainly forgotten lots of details from previous seasons. But, I'm sure there was a major plot discrepancy in this one.
Possible Spoilers
There was a mention of Freia having been in the music room in 1916 (or some year about that time), and since Hope had never seen the room, it revealed that Freia was involved in what Hope was doing. BUT, when Freia was first introduced, we learned that her mother had given her up to the other witch, who raised her. Her siblings had never met her, and it took her a while to convince them of her identity. So, she certainly couldn't have been in the music room in 1916.
