I'm sure I've read the TinyDNS package was never actually finished. Also djbDNS is comprised of two parts, TinyDNS and DNSCache. Unfortunately there is no pfSense package for DNSCache.
Unfortunately I've only ever got it to work as you hoped as result of crazy misconfiguration that wasn't too stable (had both pfSense DNS forwarder and TinyDNS answering on the same interface - would work until a reboot)
pfSense already has a built in caching DNS server that allows you to create your own A records.
For a situation where I had to use TinyDNS (to serve some SRV records), I had two pfSense boxes, if my memory serves me correctly, I had one set up as a normal router, but on this, under the DNS server settings, I set an override for a particular domain to point to the other box which was running TinyDNS.