Modding Question -- Removing AbilityBonus in CoreAbilities

Getting back into LH after the release of 2.5.  Looking at some old mod ideas I had, one was to reform the professions that a sovereign could pick from on character creation.  I was hoping to completely replace the vanilla professions through a mod (not altering the core file), but I can't remember/figure out how to do this, if it's even a potential possibility.

Thanks in advance to anyone that might have some insight into this.