Ref the possibility that they flew an "ILS" with the VOR dialled up, surely both pilots would have independently identified the ILS frequency before starting the approach?
Stranger things have happened. The NTSB report on the HOU Gulfstream accident linked somewhere above reveals that two highly experienced pro pilots did precisely that.
Of course that doesn't necessarily mean that the same thing happened here, but it's a possibility which might explain the facts as they are presently know to us. If newly revealed facts eliminate this possibility, then something else will have to explain the "new" facts.