Maybe it's a problem due to Unbound being a package and not part of the core system, but a normal configuration such as:
host hostname.example.com { hardware ethernet 00:1a:80:f4:75:ad; fixed-address hostname.example.com; } has to be rewritten as: host hostname.example.com { hardware ethernet 00:1a:30:64:75:bc; fixed-address 172.38.202.17; } thereby duplicating efforts or dhcpd will not start on reboot since pkg scripts start after everything else and Unbound has not yet been started. Also as nice as it is to have the core dhcpd create pf tables it has otherwise very limited functionality, such as lack of support for "option space", which can be used to request a system release it's lease on shutdown thereby keeping the created *_ip_tables more up-to-date. Option space is also good for preventing some of the WPAD nonsense and assisting in NetBIOS configurations. Using the packaged dhcpd would most likely eliminate the startup issue and provide the missing dhcpd functionality but one would also lose the tight pf integration.