Does AlphaVM support FibreChannel storage?

No, currently AlphaVM does not support FibreChannel.

In most cases the FibreChannel disks could be migrated to virtual SCSI disks.

On OpenVMS one can usually change the disk logical names to use DKxy instead of DGxy.

On Tru64 you can usually just set WWIDs to reflect the original disks IDs.