Minthara is too bipolar to have ever survived in Lolthian drow society, you can't be that crazy unless you're a matron mother or at least a high priestess and get away with living - someone would shank you
the fact that she has sex with you immediately is fine, Drow are like that, but it would have been nice to have more beforehand:
Minthara should absolutely explain the absolute to you. She should understand that you're from the ship and see you as a gift, she should give you the sales pitch on the religion. She should tell you WHY the absolute is building an army. She should show us the humans who are living in harmony with the absolute. Instead of murdering all the tieflings, you should kill their leaders and the rest should be given the choice to join or die.
Even Lolth's drow don't massacre everyone when they take an area. They take slaves, soldiers, etc. The Absolute should be a *less chaotic* force of evil than Lolth, and we should have some reasons why we do things. "Evil!" isn't good enough, that's not a motivation
Yes, that would be a good idea. The player should not specifically look for this opportunity himself, he should be guided and given an informed choice.
But I have an assumption that not everything is so simple with the Absolute, and many interesting situations await us in the future. Perhaps she will get rid of the tadpole, stop serving the Absolute and will be the law-evil with us, strive for personal power