Personally I'd do something like this;
1) Take out of cluster and shutdown.
2) Delete the host object from 3PAR (take a note of wwns).
3) If zoning different for Windows vs Vmware hosts update the zones (if using a 7000/8000 3par you might not have enough spare host ports to have done different zones).
4) Rebuild the host and update to current Window cluster level.
5) I'm not sure for Windows but in VMware we'd normally add it to the cluster before presenting shared LUNs, to make sure it's happy.
6) Create the new Windows 3par host object and add to the Windows cluster groups, probably a rescan or reboot after to pick everything up.
I find having any SAN LUNs visible to a host (whether correct OS or not) while installing the OS often complicates things so tend to do that last. Host object is easy to recreate so removing it at the start is a nice clean way to eliminate any chance of old LUNs being exposed.
We'd have to change the zones, the host name and the persona here, due to the way we have things setup. Luckily we only tend to move hosts between Vmware clusters so a little simpler.