I forgot to mention that there is no connection between the old and new datacenter. If there would, I would just present the new SAN space from the new datacenter to the old one, so I can just add the new OCR/Votting disk to the current ones (mirror) and then remove the old disks.
Same for the ASM and databases, but unfortunally, there is no connection between this two datacenter.
It is like moving the servers from one state to another.
are you going to have same ip addresses/subnets for public / private interconnects? The steps you have mentioned looks ok. If the ip addresses are different, you need to update the cluster config with oifcfg commands. You will be able to find that information on the oracle support.