It was before my time so I don’t know.
But I’m not really understanding the problem.
When creating a storage pool on a cluster, yes, each member must have a pool of the same name and type. But the source property used can be different on each member.
So I am assuming you want a ZFS pool as you mentioned ZFS. LXD supports using an existing zpool or ZFS dataset for its source. So you can manually create the zpool/top-level dataset however you wish first and then instruct LXD to use it.