This may or may not be successful, as the ‘Data Interoperability for ArcGIS Desktop’ extension doesn’t contain full FME functionality. In that situation, if an FME user has workspaces, they will have to recreate the functionality of their existing workspaces within ArcGIS. In the case of the ‘Data Interoperability for ArcGIS Desktop’ extension, no it cannot run existing FME workspaces.