Its not exactly clear what you are trying to achive. I think you mean that you have some hosts which are provisioned via DHCP which is linked to a DNS server, thereafter it gets a bit confused.
Do you also have hosts considered to be in the same zone but which are not provisioned with DHCP which you want to add to the DNS zone?
If this is the case, and the other hosts are on the same subnet then the simplest option is to add static mappings in the DHCP server for these hosts
If the other hosts are on different subnets, then it's possible this configuration won't work and/or won't solve the problem - my first guess at a solutionn would be to use DNSmasq which can acts as a DNS forwarder proxy but can override specific records
Are all the the hosts in scope provisioned via DHCP but the linked DNS server is outwith your current DNS resolver provision?
Simply define the zone and DNS server to your existing DNS forwarder service
if it'd be possible, I'd continue to use *.local as the FQDN
It's probably possible but not advisable. This is the best time to change it.