I'm not sure how (if) the FCT relates to the path name. I do know that a path is created via IDCAMS (it is NOT done automatically) as part of building the AIX.
You can check the cntl card library for the path name. It usually contains the 1st 7 chars of the DDNAME of the base file and uses the 8th position to make the name unique.
That's about all I can suggest. Maybe someone else has more specific info.
If you have access to the CICS proc, you can look for the DDNAMES associated w/the base cluster and the AIX. Use the DDNAME of the AIX for the I/O cmds referencing the AIX. If the file is used in batch, check out that JCL too.