Steps to remove old HDs and replace them with new ones

I'm testing OMV with 3 old refurbished hard drives, now I have ordered new HDs to start the transition from my old NAS to the OMV box.
Now i need to remove the 3 test hds. My aim is to avoid the "missing filesystem" error.

I have installed Aufs for pooling and SnapRaid for data protection.

1) remove the aufs bind share in the web gui
2) in snapraid webgui push the "reset" button to remove the snapraid configuration
3) in the ftp webgui remove the shared folder and uncheck the "enable" service checkbox
4) in the smb/cifs webgui remove the shared folder, and uncheck the "enable" service checkbox
5) in the webgui "shared folder" remove all the shared folder defined on the system
6) in the "file systems" webgui use the "delete" button (this is even possible once the shared folders are deleted and all services are disabled ???)

There are other steps to make for removing the old 3 hds and installing the new ones ?

Thanks in advance for any suggestion.

Thanks Solo, I think you're right, I will surely try the "Unmount" button first.
I hope that the "Unmount" and/or "Delete" buttons will become available after deleting the shared folder, I will try it as soon as the new HDs are delivered.
Thanks again.

Never again.
I had to uninstall all the plugin (losing all the settings), several reboots and in the end there is a shared folder that is not possible to delete.
Really, never again. A lot easier to format all and reinstall, or simply remove the disks and modify by hand the omv config .xml file.