I wrote this on Saturday afternoon, but didn't hit "post": After running fsck repeatedly until it finally stopped finding unreferenced files, I'm hopefully calling the disk array fixed on the EBN. I'm still going to reconfigure the server in some way, but for the time being I've restarted the VM for api.kde.org and the EBN. That means that api.kde.org is accessible again and the EBN is running. I'm hoping that the NIC and RAID will hold out. It will take a while for API regeneration to finish as well as a new round of Krazy checks to run.
And I would add this today: the RAID array didn't survive the night, with new read timeouts on the disk followed by mirror corruption and end of story. So I rebooted, dropped that VM again and the machine is currently running only essential services. We're in the process of moving things off of the machine now so that it is easier to reinstall, with fewer tasks. Then we'll hopefully have something usable again.