For me that would be difficult from the point of motivation, both for Margaret and for Ob. Saxby is "slightly corrupt cop boss" character, who's covering some shady stuff in hope of promotion. Among Cauldron Hill personnel only Leone Quital seems to doubt that Born is being created as secret Risuri military project, the rest think that in the end they're working for King Aodan, even if that means associating with Lorcan Kell in the process. Saxby can still bite into that, but her usefulness to Ob is extremely limited once she's exposed by PCs.
If you're looking for "bad guys" there are likely still ruins of Kell's structure in the city, even if you have apprehanded Kell himself and his leutenants. In my own campaign I promoted one of Kell's underlings as a head of new and developing assassin's guild, who's only starting to discuss the possibilities of working with Ob, that kinda worked.