Glad you listed Nettie, Apikusis, and Kagha.
I only play most CRPGs as an Elf or Half Elf (except Elder Scrolls games), but even in their barely developed present forms, all 3 characters could be among the most interesting companions, friends, or romances in the game.
Unfortunately many players missed the polite and respectful dialog choices with Nettie, and ended with the heavy handed and manipulative storyline where she attempts to poison the PC. If ceremorphosis was really as agonizing as well dangerous to other humanoids as it is repeatedly and unsubtly presented in the game, a quick death by poisoning would be the most merciful and socially responsible choice, particularly since Nettie (with the correct dialog choices) tempers her actions by asking the player to take an oath to commit suicide if and ONLY if conventional symptoms develop. She trusts an honest and responsible PC to keep their word and remember how ceremophosis endangers others. She also knows from her own research with Halsin that the player may not turn at all, or may turn differently from what happens in conventional cerrmorphosis.This is in complete contrast to Astarion's furiously emotion driven, reactive, hedonistic self centeredness and a much improved but still reflexively mistrustful and secretive Shadowheart's indifference to most others. In real life, I'm a long time wildlife rehabber working mainly with birds, so I felt an immediate bond with Nettie.
Apikusis ("the girl with the bird") was apparently put in to indicate that some of the Emerald Grove's druids opposed Kagha and were aware and fearful of her questionable affiliations, but too many players gulped down the relentlessly positive presentation of the Tieflngs (their mostly thieving, lying, amoral children, and parasitic/predatory behavior towards the Druids who sheltered and fed them was overlooked by the hordes of players who raged against the 'racist' druids who included Dwarves, Gnomes, Half Elves, Elves, Halflings, and Humans, while the Tielings varied only between Asmodeus and Mephistopheles Tielfings). Although I would like to see her as a romance prospect and potential spouse for my High Elf Druid, given how badly the Shadowheart, Astarion, and Minthara (kill those obnoxious apparently celibate tree huggers so you can have one session of sex with a hot Drow!) 'romances' are written, an ambitious modder could do a far better job. Oh, she also looks far better with any of several Half Elf head replacer mods!
Kagha is basically an almost one dimensional plot device to enrage players against the Druids as compared to the oh so virtuous and "Human" Tieflings. She has fierce, harsh, angular facial features, but I still found her far more attractive than bland featured Shadowheart, and Minthara. She quite accurately presents the generally harsh and merciless realities of "nature", which bear little resemblance to the cutsey anthropomorphism of most of the Grove's birds and mammals, or even the more malevolent and physically inaccurate anthropomorphism of Teela the viper. Her Shadow Druid "Rite of Thorns" goals make no sense from an agricultural or ecological perspective; a Grove encased by briars would be too densely shaded, dry and poorly ventilated to produce crops to sustain both humanoid and other animal inhabitants, and this would be true even in the absence of such a barrier. It is NOT possible with medieval technology to feed the Grove's inhabitants on such a small plot of land even in the absence of overarching briars. But ALL versions of D&D, and this often very good game, seem to have been written by ecological illiterates! Are we to assume that the Grove's Druids sustain themselves and a group of non productive parasitic, thieving Tiefling "guests" by conjuring food, or by divine largess from Silvanus himself?
The Jaheira romance in BG2, though completely non intuitive from a procedural perspective, was the best romance in the game, and one of the few good romances (as opposed to usual "say what your hottie wants to hear and do what they want you to do to raise their approval meter so they have sex with you" excuses for romances in CRPGs). Kagha and even the less complex Apikusis and Nettie could but probably won't be the subjects of a similarly good romance subplot.