Problems with local iPv6 DNS/DHCP resolving

Yes it is indeed, my node is utilizing it to that extent.

Not sure whether it would work or whether really it can be set to either dnsmasq or odhcpd but at least if you want to give a try and manually change the settings via ssh file browser you could see whether this works

list dhcp_link 'odhcpd'
list dhcp_link 'dnsmasq'

mind to restart related services after changes, e.g. unbound, dnsmasq, odhcpd

yeah, but it impacts /cgi-bin/luci/admin/network/dhcp - it will be a blank page , at least when your remove dnsmasq, since the LuCI code is covering only dnsmasq but not odhcpd settings.
Another caveat is that odhcpd has no feature to broadcast ntp server on the network like dnsmasq can.
Ooh, one more thing - removing dnsmasq also wipes the file /etc/config/dhcp and thus all odhcpd settings...

I am good with unbound and odhcpd but I am not relying on some script to write the local-stub zones for unbound, though certainly enticing some convenience, but rather manually creating the stub-zones for unbound. That requires though to become familiar with unbound functionality.

Suppose you will figure out what suits you best.