Good grief. That is not helpful to an investigation. That's narrative control. That is obviously what PR firms do, so that really goes without saying; I mean that the explanation is literally an explanation of narrative control and how it works.
I understand that it's nice to have a single point of contact, but I would have expected journalists to confirm things from multiple sources and question the information they were being given, not simply take the narrative they were being given by a PR firm they understand the operation of as the be all and end all. In fact, I am a little shocked. I assumed that the media had been scrutinising the foster family behind the scenes, even if we weren't hearing about it in detail due to the privacy limitations, and would have been factoring that into the reporting, but now it seems that they weren't and were in fact essentially being secondary mouthpieces for Insight's campaign.
This will have had an impact on the investigation. Whether or not the foster family is involved in the disappearance, a PR run narrative is not helpful in solving anything because it manipulates people. That's literally what a PR firm narrative is designed to do. Investigations rely on people thinking clearly and independently. And IF the foster family turn out to have something to do with the disappearance then rather than help find out what happened, this approach will have actually helped stuff it up.