GTR 25 Subaru engine

ECU/throttle body assembly let the smoke out at startup.

I am concerned a ignition coil might have shorted and caused the issue.
My plan is to order the ECU and the coils from gator tail Friday.

Looking at the wiring diagram I can’t really see anything else that could cause the ECU to burn up.

Should I preemptively replace both harnesses? I’m just worried I’m going to replace the ECU and coils and it will happen again.
I can barely afford these parts at the moment. Corona has not been kind to my family. We are getting back up but the “extra” money isn’t as plentiful as it has been.