Fredrick,
You have done great troubleshooting work here, and you sure are not getting any help from the BUDS software. It’s common to chase ECU faults that don’t cause an obvious operational problem, but here it’s the opposite.
The way the engine sounds when you isolate to Lane B reminds me of how a car engine sounds when you have two spark plug wires reversed. If this started on its own, rather than after maintenance, then I guess there is no chance that two of top plug wires are reversed (1-3 or 2-4 cylinders). That is something that may not show up on BUDS and may be masked with both lanes active. Also I see you have checked the coils, plugs and the plug boots. Have you checked the wires themselves? You can check all the way through the two cables that go to the same coil, and the resistance should be the sum of the resistance of both boots and the secondary ignition coil. Or, just compare to other coils.
One more old school test would be to disconnect a single Lane B spark plug wire, insulate the boot opening with rubber tape to avoid it sparking to something, and then do a lane check. If the problem is worse that cylinder is fine so try another plug. If you find a cylinder where disconnecting the plug wire does NOT make the problem worse, that’s your cylinder. I know you did a similar thing by disconnecting one coil, but this will refine that information.
