After a good, long, wait, hostnames work for the cnPilot R-Series routers! Change the name in cnMaestro... it changes the name in the router... and the DHCP server picks up the name!
I just finished manually updating every one of our router names, and the DHCP server picked them all up as expected. Identifying routers is so much easier in the DHCP server than before.
I'm a bit frustrated that it took so long for Cambium to actually implement this, but I'm very pleased that it is done and working.