FAC and G/P are indeed IAN indications.
IAN allows non-precision approaches to be flown effectively as a pseudo-ILS, using the same buttons on the MCP, and avoids the many 'gotchas' of flying the approach in LNAV/VNAV. Particularly useful for the hard of thinking (like me).
To differentiate an IAN approach from a real ILS, the annunciations on the FMAs are changed: FAC replaces LOC, and G/P replaces G/S. Also, the 'glideslope' and 'localizer' pointers on the PFD are depicted as triangles instead of diamonds.
It's a very nice toy that makes NDB and VOR approaches a non-event.