I would really urge the team behind to add a short intro scenario that introduces the characters to the Sight and the setting. Nothing too complicated. Just a reason as to why they all discover the sight, and why they should stick together and try to stop vaesen infestations.
I'm seriously considering altering the scenario we already have to make it just that: I would remove the Private Investigator completely, and the flyers too, and make the PCs random travelers who come back from Sigtuna to Uppsala with a night coach, and I would make it a stormy night, with a terrible accident that kills the driver and injures the horses, and in the distance, they would see the Witch Cat inn, and go there for help, only there would be no available vehicle for a day or two, and they would discover strange things nobody seems to notice in the inn... you see where this is going.
I was thinking that, after this experience, a new Vaesen encounter in Uppsala would make Linnea (or in my case, Vera, who replaces her) notice them, and only then, they could enter the Society.