Well it least we might have the problem narrowed down. Are you sure the spare plug you used is good? The coils mount on top of the ignition control module (ICM). Let'* check where the wires plug into the ICM. Unplug the connector & check for corrosion. If you don't see any plug it back in & check for corrosion where the plug wires attach to the coils. Do one at a time so they don't get mixed up.
Edit - Sometimes you can hear the spark & it can be hard to see if your outside in bright light. Should be easy to see if you're in a garage.
1999 Pontiac Bonneville SSEi (son'*)
1997 Chevy Lumina (daughter'*)
2006 Chevy Trailblazer (wife'*)
2006 Chevy Monte Carlo SS (Mine! -Zoom Zoom Zoom)