All of the elements of this crime are ipso facto allegations at this time. Everything. Even the fact that Karlie's family have accepted the bones and remains as alleged by the Coroner to be Karlie and Khandalyce have not been tested in court as yet. It really is a matter of what level of proof at this point in the proceedings would be satisfactory .
The NSW and the SA police have made assertions and allegations. As far as is known ,Mr Holdom has not denied any of them, or made a plea in regard to these allegations, he has merely appeared in court as is proper, although he didn't even want to do that. It was a matter of the magistrate enforcing this.
The time for actual verifiable , and from this I assume you mean tested in a court of law, the defence providing proof of it's deniability and the prosecution providing proof of its acceptability, both adjudicated by a judge and measured by a jury hasn't arrived yet. What you ask for is not available. Who would you expect to verify the police allegation that they have ping evidence? Some other police? some ping expert under who's authority? the Premier? . some sort of Websleuths judge, in a special websleuths court? Les Day's mum? I just don't know.