You make valid points, and I'm aware that I have slipped up at times since this version of Kaori is far more open than what the version I usually roleplay, where she's very hostile and far more bitter. The transition between rping the two versions still manages to seep through, where I've accidentally made her more open than she would normally be.

To address her apparent openness and friendliness to Humans, to be honest she actually doesn't trust them. Experience has taught her that it's better to just be friendly while quietly seething inside, since she's more likely to survive that way. The only human she actually trusts right now is Spada, since in her eyes he's proven to be trustworthy enough to keep around, helping her out even though she's blind. Even if they have offered her her favorite things, that like and openness is only temporary, and recedes rather quickly. She could be interested/like someone, but still not trust them.

It's the reason why she has two 'like' levels in her CR chart: diamonds just mean that she's interested in you, but she's still willing to cast you aside and sacrifice you if need be. The only one who has achieved the next tier, the hearts, is Mithos, and she still has conflicting feelings about that because she's afraid to trust. He's bordering between the two levels since a part of her wants to push him away still.

Also, a part of why she tends to be open and friendly sometimes is because she wants to be able to trust them. It's why she's attached to those that met her as a child, since at that time she genuinely loved them and cared for them, and once the experiment was over she was left conflicted, remembering how much she loved humans at one point. It makes a small part of her want to try again, but those trust issues and her history holds her back at the same time.

I hope that explained it, but feel free to ask for more clarification if you'd like.