I agree with GTAW, Section IX is not a stand alone code. You must also comply with the requirements of the code of construction like B31.1 or ASME Section VIII Division 1. You can qualify to section IX both processes in a single coupon as long as you list both essential, non-essential, and when required, the supplementary essential variables for both processes. The GTAW electrode will be an F6 electrode and the FCAW electrode is also an F6.
You can also by Section IX, combine two different PQRs into one WPS as long as the GTAW root process is used, and the FCAW process is used in the other as long as all the essential, non-essential, and supplimentary essential variables are within the scope of combining them per ASME Section IX QW-200.4.
Hope this helps,