SQL Server failover cluster - migrate to new SAN-disks question

Hi!

I have a 2 node SQL Server 2016 failover cluster with 3 instances with database files located on cluster disks residing on a SAN. 

I need to migrate the databases for one instance at a time to new disks located on another SAN, (the new LUNs are already added to the existing servers and added to the respective sql server instanse cluster role. )

I have done this before but it was a while ago, so I would just like some second opinions on my planned procedure below.

Step 1. Make sure to have backups of everything.

Step 2.

Stop the SQL Server resource for the instance to be migrated via Failover cluster manager.

Step 3. 

Robocopy all SQL database folders and files from old cluster disks to new cluster disks, making sure folder structure and permissions are identical.  (anyone have suggestion of fitting robocopy for this? maybe use /MIR ? Or regular copy with folder and permissions flags? )

Step 4. Switch drive letters so that the new disks have the same drive letters as the old ones previously had.

Step 5. Replace dependencies on the SQL service in cluster manager from old disks to new disks.

Step 6. Restart SQL Server from cluster manager.

This should work, right? Any more advice?

BR

Peter