Another option I was considering.....

mark all virtual services and resources as manual activation and manual
remove old server 1 from the cluster (remove - not just cluster leave)
build new server 1 as pre-migration.
create new pools/volumes to receive data on new SAN
down old server 2
now old server 1 should be the only one who sees the data volumes.
perform server migration to new server 1.
bring old server 2 back up, load ncs, but with no virtual servers or
install cluster services on new server 1 and add to cluster.
(now all clustered services should be on the new SAN, right?)
remove old server 2 from cluster.
reinstall SBD on new SAN.
Add other new servers.

will this work?