Firstly, can you not over come the reasons you cannot do a Firedrill as this is the best solution - only reasons I can think of is:

1. Not enough of storage - only need generally about 10%, depending on how long snapshot is in place and how many changes are been made at Primary and on snapshot
    
2. Enterprise licence is required do a space-optimised snapshot. 

Are these the reasons?

You can do what you want to do, however, after testing DR site, you must make DR a secondary (run vxrvg makesecondary) BEFORE you reconnect, otherwise the Primary will become an acting secondary.  You will have to do a full resync, so I would also detach rlinks before reconnecting network. Here is what I would do

1. Freeze replication service groups at both sites and application service group at Prod
2. Make Virtual replication IP resources non-critical at both sites
3. Down Virtual replication IP using O/S tools at both sites (you won't be able to do in VCS because of dependencies)
4. Verify that replication is disconnected
5. Online application service group at DR, which will run vradmin takeover, Mount the volumes at the DR site and start the DB
6. Test DR
7. Offline application service group at DR which will stop DB and umount volumes
8. Run "vxrink det" at both sites
9. Run "vxrvg makesecondary" at DR site
10. Unfreeze replication service groups and online Virtual replication IP resources 
11. Make Virtual replication IP resources Critical at both sites
12. Unfreeze application service group at Prod
13. Run vradmin -a startrep at primary site to resync data

Mike