Hey thanks for reaching out!
Make sure you seed the serial killer early. Maybe include it in Vannes' brief, if you can. The history of serial killings is potentially related to recent disappearances.
As for the scenario itself, I suggest placing 100% Organic in somewhere after Poisoned Words in the days leading up to the Masquerade to pour some gas on things and start a real fire with your Agents. Ideally you want the Agents to know Aiden (Mama Midnight) and some staff at the Black Flamingo beforehand so that when customers go missing from there, Aiden's distress over losing so many acquaintences lately can provide some real stakes directly tied to the Agents. They will likely suspect the serial killer and PH4NT0M are somehow linked. Do your best to encourage that perception.
Let us know how things went at feedback.lecham.info