ResourceStatus.Deletedin the MOAB site adapter seems to solve our problem of zombie drones outlined above. The zombie drones caused a couple of problems which required us to restart the service at least once a day. I thought this was related to a bug in the Slurm batchsystem adapter, but apparently it wasn't. Anyway, with the updated mapping it has been running for more than a week without needing to be restarted.
STARTD) but don't need them. C/T will opportunistically add them to your system. There is no problem having multiple C/T instances add resources, nor in having resources from other sources as well.