DHCP6 template

How would you handle it?

Depends on what you want. IPv6 local network just works out-of-the-box due to the MAC-to-IPv6 conversion. If you want to forward a prefix from your router, your router normally has the advertising service for this, so the MAC-to-IPv6 conversion still takes place, but with a non-local prefix. The other solution would be to use a real DHCPv6 server as you want to know, but I do not see any benefits there, do you?