My next step to diagnose such an issue would be to swap the coils around and see if the problem follows the suspect coil or stays with the same cylinder. You could take it one step further with the plugs.
If the codes indicate the problem follows the coil or plug, you have found the component at fault.
If the problem stays with the cylinder despite a different coil/plug, the issue will be with the harness plug, wiring or possibly the PCM.