So I finally found the origins of the case from this other thread.
After reading this thread in one sitting, I must commend the effort and results that have been achieved. If you ever find the time or desire, I would be interested in reading a conclusion to the project and seeing some final product pictures.
All the way through reading, I was waiting for filtration to be mentioned. In this old Whitepaper, ASHREA highlights that datacenters use MERV 11 or 13 for air entering the building, and then continuously filter with MERV 8. I am not sure how relevant this is for a home server, but I find it fitting to mention, considering how much effort has been put into considering HDD induced vibrations. Did you end up installing any filtration on this case?