Re: How many manufactures
GE, Siemens, CH and Sq D all manufacture AFCIs.
UL allows for two options when installing breakers in loadcenters;
1. Same manufacturer is allowed (e.g. Ge breakers in GE loadcenter) or
2. UL Classified breakers can be installed in a loadcenter. Classified breakers mean a manufacturer has tested and certified them with UL for use in another manufacturer's loadcenter.
Cutler Hammer offer classified breakers (including AFCI's) for all other manufacturers' loadcenters (1" and 3/4"). I am not sure about GE, Siemens or Sq D although they may also.
Looks like you got an inspector who wasn't paying attention...