Without a doubt this is the closest simulation run yet to approximate the flight path. That really is quite an impressive run. I think you may have cracked it.
Any pilot will tell you that control inputs, particularly on large aircraft, need to be made in a considered manner otherwise you will tear the wings or tail off. The aerodynamic forces really are large enough to cause instant failure of the tail if full rudder is commanded suddenly. Smooth, measured, control inputs are generally one of the marks of a good aviator. The Airbus crash in New York shortly after 9/11 was caused by a relatively inexperienced pilot violently applying full rudder inputs when they hit wake turbulence from a preceding aircraft. The tail broke away and the aircraft crashed.
Something must have convinced the investigators that the aircraft hit the ground the right way up and facing in the direction of travel. Most likely witness marks on the ground from equipment in the lower part of the aircraft or detatched parts from landing gear, etc.
At some point after that initial impact the fuselage rolled and rotated, ending up facing the wrong way and upside down. My best guess would be a wing snagging the ground and the rotation taking place about that point. Indeed there may have been a couple of rotation points with perhaps the nose digging in flipping the fuselage upwards and then a wing snagging and dragging the fuselage around before the wing broke off and the fuselage rotated upside down and backwards. It would all have happened extremely rapidly, one or two seconds at most, so plenty of room for confusion about the exact sequence.
I am begining to come to the conclusion that the description of the impact sequence was hastily written and not revised because it was not strictly relevant to the root cause of the accident or its' survivability. The investigators found the root cause of the mishap, with the broken aileron cable and were then able to account for the flight path and impact point. After that, the investigators were not too concerned with the break up sequence other than points that affected their investigation as to the cause. There was a need to be able to demonstrate the aileron cable broke in flight, for instance. Having effectively backed themselves into a corner with an early publicity release about the likely impact sequence, perhaps the investigators decided to just leave that as the official record, rather than go through the trouble and embarrassment of issuing a retraction. Such a correction might have cast doubt on the investigator's abilities or accuracy, certainly in the public's eye. I don't think there was any malicious purpose behind the inaccuracies.
To summarise, I think that you have arrived at a reasonable simulation of the flight path, one that reasonably matches the witness reports and investigators findings. You have demonstrated that the impact sequence, break up and final disposition of the aircraft wreckage were not accurately described by investigators after the initial impact point of the main fuselage. The aircraft may have slid for some distance relatively upright, but clearly it rotated upside down and end for end. The investigators did not accurately describe that sequence, but may have been constrained by a too hastily released press report. They left their report written to agree with the early press release so as not to cast any doubts on the investigation. The root cause of the accident was established and amending the accident report to more accurately account for the final position of the aircraft wreckage would not materially affect any of the findings.
I think that is possibly the most accurate account that can now be written after all these years and without new evidence coming to light.