I would start the SAN first, wait until it is started up. Then start the hosts and ensure it sees all storage devices. If not rescan.
But you can test the "resignature thing", just create a new LUN. Add one test VM to it. Replicate the LUN. Unpresent the original LUN, and now present the "replicated LUN", resignature it and then register the VM and power it on. Then at least you have tested the procedure.