Quick update:
Everything looks good and checks out.
Unfortunately, and I knew this was a risk going in, the stepper motors didn't solve the oil pressure fluctuation and alarm. So, it's probably a sending unit which I just had replaced in February and I'm not thrilled about having to go back for that. I'm going to have to try to get the shop to fix it free since it ought to work after just a few months. I've had nothing but issues with this shop, but I can't afford to pay for another one.
Nice work by Scottyboy, though. The gauge issue is NOT his doing, so don't let this disuade anyone from his work.