I saw those options in character creator (greyed out for now), but that would be just for the 1 character we pick, unless we play a custom character, and I likely do.
What I meant here is an option to edit the companion builds when we accept them in the party: STR, DEX and other stats, proficiencies, bonuses, everything except looks, race and class (unless a very similar class maybe).
They should keep all story options, like Shadowheart being still a cleric of the trickery, but having a heal based build if we want so. She don't have to know that based on her build, she no longer worships the same God. Same with the others.
Otherwise a party made from custom characters will be better in fights, and then all that effort related to story companions would be wasted.