Saga Update:
I took my car to a second SC on Feb. 16 and explained the issue. A tech. drove the car and agreed the noise was unbearable. They said they would do some troubleshooting to determine what the cause was. I also asked if they could verify the penthouse perimeter seal was present and they agreed they would. I showed them a video of the noise and (what I believed was) the missing penthouse perimeter seal and they told me to send the files to them so they could add them to my service file. (I sent them a link to dropbox)They got back to me later that day and told me the rear-drive unit needed to be replaced but they would need to order the part and scheduled a new appointment for March 1st.
I took my car back on March 1st and they replaced the rear-drive unit. I got a call and was told the noise was still present and they would need to do some more investigation and asked to keep the car another day; I agreed. They called back at the end of the day on March 2nd. They figured out what was causing the issue. It turned out to be a...missing penthouse perimeter seal.
Picked up my car today and the
issue has been resolved!
TL;DR: Issue Resolved; missing penthouse perimeter seal.