Are Lizzie and Josie sirens?

Wouldn't make sense. They were able to siphon magic from Seline, suggesting that even psychics are magical beings. So if you need magic to be a psychic it should not be possible to be a psychic siphon. Although, apparently siphoners can siphon off memories as shown by Oscar, so maybe that has something to do with it. It seems to mess with powers that are mentally triggered, since there are no witches around to test that who knows, but maybe it would affect them too now that we know psychic powers are magically based suggesting psychics like siphoners are another subspecies of witch.

Nemo Unus Animabus Carnem!

I had the same thought as well, and while it is not likely, it's always possible that it affected them, just because the are children. Maybe that frequency that the fork produces, has an affect on children, and the whole thing of it affecting them could be just to make us think they had siren potential, a decoy of sorts. Because the no other children have been around the fork. But idk, who knows really..

I thought that maybe they siphoned off Selene before, maybe by accident and they possibly gained some of her magic and her weakness as well, however, as a siren she can project and aim her psychic powers, so maybe she has been singing to the girls and they have been unknowingly taking her magic in that way, especially if she is doing it while they are sleeping, it may even have something to do with the girls being twins, they say there is a psychic bond there, and maybe the fork works on them because they are more psychically in tuned.