Possible I suppose but they went at him awfully heavy if they were just creating a ploy for other things? To be honest I don't give them that much credit. Their work is most often done with a heavy hammer rather than a scalpel? The predawn raid on Manefort's home with gun's drawn is more the FBI and Rosenstein's style: blunt and with overwhelming force.
The last point I neglected to include above:
4) If this boy scout Aussie was the underlying source which triggered the investigation, WHY IN HEAVEN"S NAME wasn't this put out a long time ago? There is nothing bad which will come of exposing his name and his revelations to the Congressional investigators so why would they demure, back peddle and refuse to comment so intensely about it? It makes no sense for them to be hiding these facts if indeed there is any truth to the matter. Indeed, it might be supporting facts in the FISA request and it might have been something they added later when it became known to them and the original request was turned down. But it makes no sense that this was the only smoking gun presented to the FISA Court. Doesn't pass the smell test in my opinion.
4) - excellent question. Someday we know the answer.