I don't believe you will need to copy databases around.
When you change the IP address of the ports on NetApp filer, you will probably need to re-establish iSCSI session from the SnapDrive. Then SME it should pick everything up, or, if it doesn't, you will need to run the setup wizard again.
If SnapDrive doesn't pick up LUNs straight away, I'd do disks rescan in Windows 'Disk Management'.
Your step 5 describes changing 'preferred IP address for management traffic', which not necessarily will change at all (your management traffic can still go via different port / IP address on the filer, not the same as iSCSI port)
How ever the Filer IP will change and the Server will have to connect to its LUNs via a new Interface (one that is in the new subnet) how should the Server be able to pick them up straight away ? how shall he know the new IP of the filer....