DCN

Update for anyone who stumbles onto this in the future...
 
I have successfully "fixed the server" unfortunately it is not clear on what the "fix" was. I replaced the HBA card which did not immediately change anything, I replaced the mini-sas cables which did not immediately change anything, I pulled all of the drives out booted and then re-installed everything while monitoring the HBA card which still did not see any drives. I was about to order a new backplane when I stumbled into the fix.
 
After days of squirreling around with no results I happened to re-seat the HBA card, re-seat the mini-sas cables, re-seat 1 molex connector, re-seat the IPMI connection, and pull out the unRaid Boot USB with all of the drives out. I had verified that power was still going to the board/backplane/HBA and I was checking the individual connections on the backplane. So I booted the system and put 1 drive back in while monitoring the HBA card and IT ACTUALLY READ THE DRIVE AS PRESENT!.... Slightly panicking I gingerly put a second drive in and it saw that one to! I put all 21 drives back in and to my utter shock they all showed up! I shut the system down and replaced the unRaid boot usb and voila everything came back and my unRaid system acknowledged that all drives had been restored.
 
Yes, I know that you are supposed to only change 1 thing at a time but this was the 6th day of troubleshooting and I was just throwing things at the wall to see what stuck. Hopefully this will help someone or maybe just keep their hope alive haha.
 
TL;DR sometimes the planets align in a certain way that allows for the same action to be repeated yet different results occur haha