...she was never meant to be a companion originally...
I'm not sure that's true. She was always coded differently. Whenever you looted her corpse (even in the earliest days of early access), her armor disappeared from her body, as it does with a companion, which is to say as it does not with a non-companion.
To my understanding, she was always meant to be a potential companion, at least as far back as we can reasonably look.
