My new guess:
Seeker with guardian 0-2(Geroge? Harvey?) or interesting requiment.
Maybe Harvey with Insight 0-5?
Or maybe Amanda with Talents?
For Rogue/Survivor Daniela?
Amanda and Daniela are most likely IMO.
With the recent spoilers, it might be no additional neutral investigators. So my guess: Charlie: Guardian, Trish: Rogue,Gloria: Seeker,Wilson: Survivor and we ill probably get a new mystic investigator.