The latest rumour that I have heard is that the seat will be taken by someone connected to Wilson Security who doesn't currently have anything to do with V8 Supercars (Blanchard is expected to move over to the ADVAM car). Which makes sense for two reasons - one, Wilson Security is backing the car, so obviously they'll want someone they know in it; and secondly, I'm not aware of any V8 Supercar drivers who are out of a seat, but have a connection to Wilson Security.
Daniel Gaunt is the name I've heard mentioned the most in this regard, since he competes (or has competed in the past) in the Carrera Cup with sponsorship from Wilson Security.