There has been a building on that location at Essendon since at least 1962 when the old DCA hangar was relocated there to serve as home for the Regional Transport Depot.
Don't think so. And don't forget that the end of the runway is nowhere near where it used to be.
There are a number of lawyers looking at this in detail at the moment with a fistfull of FOI requests. I suspect the ATSB initiating separate report on their own initiative suggests that there is a real issue.