The pin-outs for the DAC interface board have been determined.
Turns out that my deductions using the D0902496 wiring diagram, a spare D080303 DAC to IDC adaptor and a multimeter were correct! The pin outs as determined by this test are sketched in the graphic below.
The excitation points added to the simulink model are still there, I plan on keeping it as such till I finish installation of the boards as they will be useful for testing purposes.
Pin-Outs of the DAC to IDC Adaptor (D080303) inside the "DAC Interface Box at 1Y4":
Makeshift break-out ribbon cable: