Hello there,
As you are sure that there are no data in volume even backup then there is no harm in pushing the delete. You can also simply use the PowerShell command to achieve this.
The Remove-ClusterSharedVolume cmdlet removes a volume from the Cluster Shared Volumes in a failover cluster and places it in Available Storage in the cluster. After placing a volume in Available Storage, you can use the volume when you configure a new clustered role.
This might help in some precautionary steps https://social.technet.microsoft.com/Forums/ie/en-US/bf4129dd-21f4-4fa0-b3d5-51ed6d57c976/remove-cluster-shared-volumes-and-readd-them?forum=winserverClustering
--------------------------------------------------------------------------------------------------------------------
--If the reply is helpful, please Upvote and Accept it as an answer–