@Coro brought up some good points, the advanced resolver debug logging should show why no host names are picked up. I also updated the original discussion. What you are asking for should now be possible by adding the corresponding superclient_id to all of your ip-[...] MAC address entries.
PLUS: It is also possible to transport the MAC address over your router into FTL as FTL v5.2 is processing EDNS(0) information to get the IP and MAC addresses of the original requestors even if hidden behind a NAT (and enabled on the router).
See