BBF, not being flippant but, in all probability, so were these pilots VMC until just prior to the crash, ie before waypoint change. Certainly though they were IMC soon after that until they did crash. So your final thought of "Classic CFIT" deserves inspection. If it was then case closed, but the evidence offered to support that (Boeing's Model) has been disproved and the crash site evidence strongly suggests that the aircraft was not in control immediately prior to the crash. So not so much Classic as Confused and thus not so much CFIT as UFIT?