Had one additional HW failure and was not able to see any disks from the array using the "format" command. Had to replace the SAS controller, after which I was able to import the pools created, and can now access the files.
You're right. This has been a "very low probability, very high impact" risk, that just has not been mitigated. This was maybe too close of a call.
I'm actually now setting up a repository for the files from the old server. Moving the whole system we have to a standalone client based system, with critical work files stored in a data center version control. Anyways, need the files from the old server...which I now seem to have