I will not be modifying the brake or abs systems but the ecu will no longer get any info from the now missing 4.0 other than alternator signal.

with compushift running the trans the tcu will also not be getting or giving signal.

 

@PickleRick one last try the D2 has 4 computers ECU, BCU,TCU,SLABS if you have not gotten this far in your planning and research and still do not understand what they do and how they interact you are going to fail.

The ECU not getting signal will toss a butt load of codes and light your check engine light.
I am assuming you have an 03/04 disco if not your transmission may not work with the compushift device, the 9 pin connector may not be there. The TCU becomes irrelevant as I understand the Compushift device.
Traction control runs off the SLABS, not the ECU 3 Amigo's can still appear - I am not sure possible ECU/TCU interactions here but they should be minor as it is all about wheel speed sensors and the ABS system
Low range/Hi range/CDL will work but not have the engine mapping for best performance, LR does some engine mapping for those as I understand everything
BCU is irrelevant I believe

 

i have a 99 rover but it's high miles and the zf4hp22 won't like the diesel torque for long. She's got almost 230k

I have a low mile zf4hp24/ complete sub 90k mile 2003 for parts.

With the 4.0 removed I will no longer care about the SES light. I've not looked close enough at the cluster but the bulb will either be removed or tape will go over it.

The om602.962 is a mechanical diesel, I just need gauges.