The older ones actually should be even more intuitive. At FMS inserted MDA -50 ft, the AP should trip off and FDs revert to basic HDG-V/S modes. Mode announciators boxed on FMA, FD bars flashing, and audio triple click.
In your graph (lot of meticulous work behind it!) do I read it correctly that the vertical axis reference is corrected ALT, thus the corrected profile line is different from the geometrical path green line?
Secondly, to leech on your research further: Does the report mention anything about the V-DEV indicator (yo-yo / doughnut) and indications displayed on the PFD?
Thanks.