A quick update...I had the transmission removed from the car to install a new clutch some weeks ago. While the trans was out, I replaced #6, 7, 8, 9 in the diagram below. After reinstalling the trans, the vibration was reduced to an acceptable level. the vibration is certainly still present, but not so annoying I don't enjoy driving the car. Additionally, if you're planning to replace #6, 7, 8, 9, you should plan to buy 4 (qty: 2) and 5 (qty: 2) as they will be damaged upon removal.
https://www.realoem.com/bmw/enUS/sho...diagId=23_0968
Hope this information is helpful to someone in the future!