In my case, I sorted the "warning: increase ulimit or decrease threads, ports in config to remove this warning" by changing...
num-threads: 15
to:
num-threads: 4
where 4 is the total number of cpu threads on my docker host.
As for "error: Could not open logfile /dev/null: Permission denied", I've sorted this by creating the "unbound.log" inside the chroot directory, which is the mapped appdata directory that I mapped the unbound docker to.
For the rest of the errors, I'm still in the process of sorting them.