Well I finally had time available to work on the Bonneville.
I had received a known good ICM and PCM from a friend on the forum. I replaced the ICM first and the car still wouldn't start - as usual. So I disconnected the negative battery terminal, pulled the PCM and did the chip swap and installed the known good PCM. Put everything back together and she started up right away!
So thinking it was just the PCM, I swapped the ICM back out and put my original back in place. Started it up but ran rough. Swapped it back out with the one I had received, and it ran beautifully.
So it was both the ICM & the PCM causing all of the problems. I have yet to take a drive anywhere, but I have to go into town this afternoon so that will be the big test. I suspect I will have no problems.
Thanks everyone for all of your help and a special thanks to BillBoost37 for providing the known good spares and getting my Bonneville back to peak running condition.