Actually, both Minthara and Dror Raggzlin (the hobgoblin) have VERY! human motivations, which you can find out if you use detect thoughts on them. They both just want to please the absolute and seize power and authority. Ofc they are part of the potentially brainwashing cult, so we can't be sure if this is what they really desire. I think those true souls should be considered more as pawns with just a hint of their own alignment and personality, not full-scale characters, at least, not yet. True soul Nere on the other hand can be turned away from the Absolute by persuading him and exposing him to the truth and even Minthara in a certain sequence can violate a direct order from the absolute to kill you at camp. So not so sure about this whole aspect yet.

About Halsin, I think he is definately good in alignment, but he comes with a twist of a cunning mind. I find his philosophy and character convincing. If you kill Kagha, he plays politics and assigns an expatriate to lead the grove, because he thinks that it is corrupt on many levels. And he can't hold it by himself because he is selfish to leave the grove and pursue his own goals near the moonrise towers. That leads me to a thought that being good is not bad and being bad is not bad (jokes aside). Because you can't be either 100% and the game portrays it always OK, but sometimes not great. I'll give this a second look in my next playthrough.