Something from the other thread that I had not seen mentioned before
https://www.pprune.org/australia-new-zealand-pacific/611016-douglas-haywood-ross-kelly.html#post10195432
It is stated that the FO on the accident flight, Ross Kelly, had an engine failure in another Convair last year. So one of the flight crew had first hand experience of the CV-340 on one engine even if at a very light weight.
Not sure how that would manifest itself in this case, but surely better than having no experience of engine problems.