Not sure what you are allowed to do regarding /dbfs, dbfs, for that matter. It is part of the securefile development group and within the XMLDB Realm of things, "we" only make it visible, although it is now a supported part in Oracle 12c. Privileges etc work in dbfs differently than in Oracle XMLDB.
As mentioned in the Securefiles and Large Objects manual of 12c:
> "Note that features implemented by the XDB repository, such as repository events, resource configurations, and ACLs, are not available for the
Therefore from a viewpoint of XMLDB server protocols, it is difficult to get it setup the way you want to and/or (if doable) this will be supported. DBFS (NFS) has been implemented differently than the XMLDB server protocols (HTTP, WebDAV, FTP, ...)