The toolset seems to be campaign, map, etc based... I'm wondering if there's a way to create a skill (using existing mechanics) by the toolset, or if it has to be done with file modding elsewhere somehow.

Namely - I think a mind control wizard would be good fun. I think it's dumb that all the charms are dex based. Makes little sense. I'd like to make a mind control spell but have it be int based, likely in hydrosophistry (as it's a support school so it's less unbalancing to give it that CC option).