There is no indication that she missed the photoshoot on purpose after scheming with Axel. Is there a possibility? Yea, but anything not specifically ruled out could be seen as a possibility. You seem to view all the characters through your own worldview, which is fine, but it generally take a bit more nuance than that to analyze a character objectively.
Ivy is certainly not a pure girl. But is she malicious? In her mind (and even in Lena's if you play her that way), she is helping Holly break out of her shell. Being so shy and hung up about sex is not a healthy way to live according to her worldview. There is no indication that she is being manipulative for personal gain. At most, you could argue that she takes "advantage" of Holly's innocence, but it's not even like she is training her to be her sex slave or something. She finds her cute and wants her to grow into a more confident girl. Since sex means nothing to Ivy, it is not a prime motivator to "corrupt" Holly for personal gain. It's just something Holly herself enjoys and Ivy doesn't mind partaking in some Holly action.
She is basically like a girl version of Jeremy in a sense. She is a wingwoman for Lena and gives her good advice on most things (in her sexually liberal kinda way). As long as a character's actions and worldview are within the acceptable spectrum, you gotta look at their motivations to determine their worth as an individual. You hate Jeremy, so you hate Ivy. Makes sense. They are pretty similar. They are bros to Ian and Jeremy respectively, but if you personally are against everything they stand for, you might think they are bad people. Again, neither of them are the typical pure, reserved people with outstanding ethics, but they are written to be good friends.
As for Ivy vs Louise, it is Louise who has an axe to grind against Ivy. Ivy doesn't really care. She finds it funny to rile her up because Louise is incredibly toxic towards her, but it is more of a one way rivalry. As you can see with Stan, Louise isn't the most understanding person. She is quite closed minded and has her own slew of psychological issues which are quite frankly more toxic than Ivy's straightforward nature.