If I clearly understood your scenario, you want to use remote NFS datastore for both sites and replicate VMs using the same storage.
Is it possible to deploy Veeam Backup Proxy on the storage site?
To collect, transform and transport VM data during the VM replication process, Veeam B&R uses Veeam Data Movers. For optimal data retrieval process, proxy should be deployed close to source and target datastores.
More detailed information about Veeam Replication scenarios can be reviewed over here: Replication Scenarios