I ran into a fairly similar problem with BIND v9, although I corrected it by adding:
--snip-- query-source address x.x.x.x port 53; --end-- I'm not sure how you would apply this with tinydns, but I figured this might point you in the correct direction. As far as your pf.conf goes, if I were you, I would add before all of my filters, "block all." Just a suggestion though. -- Brandon L. Carr