So, were all the affected VMs restore points in this state or did you make a change to prior to the last restore point?

The "(device unavailable)" setting looks like the catalyst for the error. My guess is that when Restore Rehearsal attempts to create the VMX file for the new VM, the invalid configuration for that device is detected and the error is thrown. Perhaps a normal restore (where you are overwriting a VM rather than creating a new one) works because that process compares settings in the VMX files? It would be interesting to see what occurs when restoring with an invalid configuration setting over a valid configuration setting.

During Restore Rehearsal you can choose a different restore point by clicking on the "Source Selection" link in the wizard.