BIND (and possibly others) have been doing a lot of work on fuzzing DNS input, should probably do the same. May make sense to finish #14 first to find any low hanging fruit.
As a basic test of parser error handling, this could start with just sending random snippets, like: head -c 128 /dev/urandom | netcat -u 127.0.0.1 53
It's a bit quiet in here.