- That's not true. You can format the VDisk file system in any format with any supported cluster size.
- If partitioned, yes.
- Sure; ReFS is best for Hyper-V.
- 3 is going to be the most likely; if the disk you plan to allocate a new volume to isn't partitioned today and has no free space on the volume, you won't be able to shrink it and partition it. This also may require 3rd party disk partitioning utilities.
- Standard provides you with 2 Windows licenses for VMs. Data Center allows for unlimited Windows VM installs.
What I would talk to the customer about is performing a backup of all VMs, format the disks on Hyper-V as that cluster size isn't appropriate for VMs, then restore the VMs. That will save on hardware costs but will require downtime of the Hyper-V server.