Well, it died again. Same symptoms as before - replaced the igniter again with used OEM part, no change. Bought a brand new coil, no change. Bought a brand new igniter, no change. Verified 12v at the igniter, verified 12v at the coil, verified continuity between ECU and igniter, and even changed the ECU to send ignition signal out another output (in case ignition #1 driver was bad).
Still won't run.
I have an oscilloscope on the way to help narrow it down. On the bright side, I moved as of Jan 1 and now have a heated garage.