Yes, of course we support multiple cabin crew uniforms and, in fact, we have 227 different airlines recognized.
If it was another airplane, I might suggest the icao_airline code was missing, since many developers don't know about that (they port stuff from FSX/P3D, and this is a new MSFS parameter in the aircraft.cfg), but I'm sure all Fenix liveries, at least the official ones, have the correct codes and many of them are included in GSX.