I don't think it would be sufficient. There's more to DNS in an Active Directory network than just zones and cname records for host-name to IP address resolution. AD uses DDNS to store numerous records of AD related objects (domains, DCs and GCs are some of those most important objects).
DCs and GCs can use DDNS to automatically enter in their SRV records.
If the DNS server has the appropriate records for everything AD needs, then it'll work. If not, AD won't work and neither will Unity.