Power cycling c1dcuepics seems to have fixed the EPICs channel problems, and c1lsc, c1asc, and c1iovme are talking again.
I burt restored c1iscepics and c1Iosepics from the snapshot at 6 am this morning.
However, c1susvme1 never came back after the last power cycle of its crate that it shared with c1susvme2. I connected a monitor and keyboard per the reboot instructions. I hit ctrl-x, and it proceeded to boot, however, it displays that there's a media error, PXE-E61, suggests testing the cable, and only offers an option to reboot. From a cursory inspection of the front, the cables seem to look okay. Also, this machine had eventually come back after the first power cycle and I'm pretty sure no cables were moved in between.
I had a go at trying to bring c1susvme1 back online. The first few times I hit the physical reset button, I saw the same error that Joe mentioned, about needing to check some cables. I tried one round of rebooting c1sosvme, c1susvme2 and c1susvme1, with no success. After a few iterations of jiggle cables/reset button/ctrl-x on c1susvme1, it came back. I ran the startup.cmd script, and re-enabled the suspensions, and Mode Cleaner is now locked. So, all systems are back online, and I'm crossing my fingers and toes that they stay that way, at least for a little while.