Gary Jubelin wrote a 7 page letter to the Coroner (his opinions), giving her what he thought were salient points.
David Laidlaw supplied his Statement of Facts (which turned out to be opinion), giving the Coroner what he thought were salient points.
I don't think Hans Rupp provided anything separately, though whatever happened in the first 5 months of the investigation would have been in the police brief.
The Coroner probably believed nothing further could be obtained by calling them to the stand.
imo
