And downplaying the evilness of certain other companions doesn't fly. To claim Minthara is the only truly evil companion is just plain silly. Three companions are outright evil, and at least two more have strong evil leanings at a minimum.
I'd argue Jaheira being true neutral is more of a formality if anything because the original druid kit had that as a requirement. In practice she's leaned a lot more into good in the previous games. Also it's been a long time now and things could have changed.
Agreed, Jaheria leans heavily towards 'good', whatever that means now. I don't remember being able to get her to leave by being very good, but you could easily get her to leave if you were very evil.