Thank you for the reply.
You are correct. No. I only told it to conditionally forward IPv4 -- partly because the web UI seems to be somewhat IPv4-centric.
Thank you for the pointer to how to configure additional conditional forwarding - it was something I had made a note of when I was doing the original setup and simply forgot about. I suspect because I do not have this additional configuration none of my IPv6 addresses are being sent for reverse lookup. Of course - as pointed out in my original post - my OpenWRT DNS isn't reverse mapping all of the IPv6 addresses it assigns (each client gets more than one). I'm not sure if this is an OpenWRT bug, or just how things are in IPv6 land.
Wow - your post appears to be exactly what I'm seeing. I'm going to have to read through that and make a few changes to see if this gets better.
Yes - I meant DHCP. My OpenWRT manages DHCP and maintains the local lan DNS. Pi-hole is configured as every client's DNS server, and should smartly forward things to the right places.