I don't see any supporting evidence to this conspiracy theory that this is some sort of tactic to make someone(specifically FFC the primary POI) that is allegedly capable of doing what they have allegedly done cracking. I feel like this is a narrative some people are lifting from a bad episode of Law & Order.
I do think the police want to make a public show of competent investigational methods for a multitude of reasons, namely public faith in the NSW police force in light of the tunnel vision of prior investigators that will continue to cost the NSW taxpayer for many years to come and especially in light of the CS investigation.
I would be gobsmacked if FFC does not protest her innocence to the grave, if she is involved it would be completely inconsistent with all her previous actions and statements to acknowledge any guilt at any stage. If she was involved you don't simply live with it for this long and suddenly crack because of some news reports or journalists outside your house, anyone involved in this that has covered it up would in all likelihood need to have a particular personality that allows for you to sleep at night with the knowledge innocent people are having their lives destroyed because of your lies.
This operation is dedicating a significant amount of police resources and tax-payer dollars on the off chance it might make someone crack? There are far cheaper ways of doing that believe me.