Can I easily re-use a domain controller's hostname and IP after its removed?

I have two Windows Server 2003 domain controllers that a lot of systems (100+ hosts) on our network point at for their DNS.  For the sake of explaining I'll call them Old1 and Old2.

After I have demoted the DCs Old1 & Old2 and removed them from the domain, could I re-use their names and IP addresses without any problems occurring?  They will be demoted and then their computer objects deleted.

Ideally to save having to change all the systems to point at a new DNS server, I'd like to build 1 new 2012 DNS server that has the same names and IP addresses

i.e. the new 2012 DNS server (not a domain controller), will :

- be called Old1 but also have an A record in DNS that points Old2 at Old1
- have two network adaptors,  one using the same IP as Old1,  and the other as Old2

I would hope that DNS requests made to either the two IP addresses,  or to either hostnames Old1 or Old2,  will respond correctly.

Does that make sense or need more detail?

Thanks
Stuart