Thanks for the extensive history. This will help us from asking most of the normal questions. I do still have a few:

What is a "blown ECU" in this frame of reference? Is it just the loss of fuel pump relay ground when the ECU gets an ignition pulse signal from the ICU (hybrid chip)?

"• Check Diagnostic codes and get code from port #6 (Coolant Temp Sensor) but when check port #2, No reading at all. Forums suggest blown ECU." The actual codes would be more helpful.

So, you ask what we think it is...here is my vote:

"3rd: Ignition Switch faulty? (Explain no shut off but would this fry ECU? Don’t believe so & car shuts off as should when remove fuse #6 before attempt?)"

First fix whatever is going on with ignition switch, then...

I am not convinced the 951 ECU's are fried. If they are and it is the hybrid chip failure it can be tested with the fuel pump relay hack (temporary perm ground for terminal 86-2). Use an old ECU to test from here on out until all you electrical gremlins seem exorcised.