Beez,
No doubt your head is spinning right now. I'm sympathetic. I went back and re-read the entire thread.
I stand by my suggestion to approach the dealership who added the incorrect fluid. In the worst case scenario, this fluid may have caused or contributed to the demise of the transaxle itself. You need to inform them to see if they will offer any remedy. (Keep in mind, that you have proof in 1) the receipt with the incorrect oil; 2) a sample of the oil that you extract from the transaxle; 3) your video recordings of the noise.)
In parallel with this activity, I would drain and re-fill the transaxle with the correct fluid. (If you need any, let me know as we generally have a case or two in stock.) Take and share a pic of the magnetic plug on the passenger side of the transaxle and also the screen from the plug on the driver's side. I and/or others can let you know if the appearance is "normal". Drain the fluid (4 quarts) into a clean pan and take a close look at what comes out. Look for any signs of metal flakes. I would leave the pans off of the car and go drive the car a bit (20 minutes or so to let the fluids come up to temp) and then I would come back and drain and re-fill it one more time.
I would like to think think that there's is a better than 50% chance that the noise will disappear. A lubricant with the wrong properties can cause all kinds of odd anomalies - not the least of which is components that should retract from a position and don't or vice versa. These can all contribute to the noises you heard/recorded.
They VERY best outcome from my perspective is that the dealership - with the video evidence that you supply, agrees that their error has jeopardized the transaxle and they will pay all or part of a replacement transaxle. If they do this, I would recommend paying the core charge which allows you to keep the current transaxle.
As FYI, last I checked, dealer cost on the transaxle is approximately $13,500 and there is a $3200 core charge.