We have ways to add abilities via cheats and even change the character's class.  However, is there a way to remove unwanted abilities or change race?

 

My ultimate goal is to respec existing companions to be in line with ones you can hire - not better or worse.  I can easily adjust their attributes and subtract the gold I would've spent on hiring to have party banter/interaction without negatively impacting combat performance.  I can even add racial abilities from any race to compensate for companions' subpar race choices.  Unfortunately, I can't find a way to remove existing racial abilities or change the race, along with its bonuses and would appreciate if anyone has figured out a way to fully "clean up" companions.

Did you try using the console and the RemoveTalent command?

 

See here: http://rien-ici.com/iemod/console

 

You can find talent names in PillarsOfEternity_Data\assetbundles\prefabs\objectbundle