Network config question for disaster recovery test

We have a Disaster Recovery (DR) test coming up and we'd like our Isilon available on both the DR network, which is isolated from Prod, and our Prod network.  Additionally, we'd like read-only access during our DR test to several replicated folders from this Isilon. They're replicated from a remote site to this Isilon.

Replicated Folder: \ifs\repl\data
We're using smb shares mainly (share permissions are everyone/full control) but there may be some NFS (v3) exports too.
NTFS permissions are applied at the remote site from the AD domain SIERA. These permissions would be part of the replicated structure.
Both the Site 1 and Site 2 Isilon clusters are part of the same domain, SIERA.

Site 1   replicates to   Site 2

Site 2, using VLAN tagging, would connect to both our prod network and our DR network.

We'd have our Active Directory domain available on both prod and DR networks.
However, the domain controller on the DR network would be a clone of prod and wouldn't be allowed to talk to the prod DC.

So then I have several questions:

Is this possible? What reconfiguration on the Isilon is needed?
   Trunk the VLAN associated with the DR segment to the Isilon
   Create a DR subnet and pool on the Isilon in the Siera domain
   What about DNS settings on the Isilon? Do I just add the DC on the DR segment to the list?
   How does adding the isiloated DNS server affect everything else on the Isilon?
   Depending on when the DR segment and the DC are built, it seems like I may need to add an SPN for the new smartconnect too.
Is anyone doing DR tests similar to this? Or better question: Does anyone have a best practice configuration for doing DR tests?

-- Thanks