Is this the correct approach for default anatomy with 15002V?
Correct with respect to what?
If you need to run CAT12 on the MNI ICBM152 template because you need a volume or surface parcellation that is not available with the default FreeSurfer segmentation: yes, it makes sense. Otherwise, I'm not sure why you would do this.
I will at some point update the ICBM152 template used by default in the Brainstorm protocols to include the CAT12 atlases.