Cool theory. One nit to pick--I dont think Mavra attacked Harry and Thomas for no reason. I think she was gunning for *Thomas*. During the first attack Harry hadnt even been officially hired. Then at the party, when she learns of the attack, Justine says something like, 'I thought you didnt have to worry about Mavra'. Then, during the attack outside the movie studio, the MavraPuppet talks about Thomas as 'the one who betrayed us.'
I had been thinking of all that as Mavra having a beef with the White Court in general over the Stokerlypse rather than Thomas in particular, and doesn't Mavra, during that attack, characterise Thomas, Lara and Inari all by their relationships to Lord Raith, suggesting he's the one she sees as her actual target ?