My bet is Ms. Loren, especially after her Beagle Point speech and then specifically coming back to Prism and all chaos ensuing. Which would also mean the Dark Wheel.
Of that list, Lady Kahina is the least likely.
The Children of Raxxla's current thinking is that some authority behind the scenes is pulling strings to remove pieces from the board.
The CEO of Metadrive, Femi Dakarai, committed suicide (was murdered) after financial irregularities raised by Sirius Corp.
Cmdr Raan Corsen runs with Metadrive data and is chased by unknown pursuers to Alioth, where he crashes.
Senator Kahina Loren, also known as Salomé, is detained in Cemiess. Stripped of her title of Senator. Sent to her home system for a trial. Trial is held behind closed doors where she's sent to a prison at the far end of Empire space. She's effectively silenced.
Sirius Corp buy up Metadrive and it's new drive tech at a huge discount.
Salomé is always warning to be wary of politics between the superpowers, and concentrate on the mysteries outside of humanity's local area.
UAs, UPs, Barnacles, crashed alien ships, ancient ruins, whispers about the faraway EAFOTS sector... these are the things to concentrate on.