Ignition coil module suspected faulty, can I switch modules around?

Never seen it and considering there is nothing electronic in that area there is no way for it to cause an issue with the electronics. The only difference between the vacuum unit and the electronic is that one uses a stepper motor to open and close the pintle instead of vacuum.
The stepper motor is fully enclosed inside the grounded motor housing on the top of the valve. The engine it was most often used on had the same EGR valve your car has.

Pretty much every OEM will tell you that using any part they don't provide is bad and aftermarket suppliers will tell you that their parts are better than OEM. Then there are parts like these gaskets. The OE doesn't like them because they demonstrate there is a problem with their product. The supplier on the other hand tosses them out there with more or less a "use at your own risk" attitude. Thing is that I've installed a few hundred of them after cleaning carbon out. The most common issue? The engine is still making carbon from oil use and the screen plugs up first. Then you take it out, clean it and put it back in, or more commonly you just replace it. I've even run across folks who had the same though but didn't know they were sold, those took 2 gaskets and some stainless mesh and made a sandwich gasket. Have yet to see a single problem and most of those vehicles are now off the road after NY salt ate them. But they went a lot of miles after the repair.

When I hired for the shop, I always looked at actual experience over ASE or other paperwork for the same reason. There are a lot of ASE certified folks just out of school who can do the job, but there are also some who learned how to take the tests but cannot really handle the real-world application of the material. I have friends down south and out west and I keep threatening them that I'll bring a few salt belt cars to their shops so they can learn the fun of dealing with real rust, not the piddly orange coating you can wipe off with a finger.

Since you have a different code than what we started with I'm going to have you ask that as a new question, just to keep our search system happy. Please mention that the 401 came back and the passages have been cleaned out.