I understand what you are saying, I agree that Ian and Lena are a fundamental part of any transformations Holly goes through because their soft influence is what gets her to come out of her shell in the first place. Even if she had somehow met Ivy without Lena, she wouldn't really listen to anything Ivy says because Holly's "shell" and Ivy's rather aggressive attitude would have inevitably driven a wedge between them.You got me on that, call it professional deformation. However, your main argument was that corruption was happening only through manipulation or coercion, so I was disproving that.
If Ivy was the only one contributing to Holly's corruption thanks to her manipulation, how would you explain that Ivy's same mean and coercive suggestions even with encouragement from Lena are rendered completely useless if Holly is dating Ian? Obviously it's not enough, Holly needs to be in the right mindset to be okay with those suggestions, and that mindset is affected by primarily Ian and Lena (even if they were NPCs).
It wasn't my intention to diminish Ivy's clearly significant role in Holly's corruption, only to showcase that Lena's role as a gentle guiding force is much more important (if Ian rejected her obviously) to Holly's corruption and she doesn't need to resort to manipulation or coercion, only encouragement but ultimately allowing Holly to make her own decisions. Ivy provides opportunities, sure, but whether Holly takes those opportunities and listens to Ivy's advice is mainly decided by Lena's direct or indirect influence because Holly always looks up to Lena as an example and she values her words over Ivy's. I hope that I managed to make myself clear at least on that.
To summarize my points:
1) Is Ivy the main instigator for Holly's corruption? Yes, no argument here.
2) Can Ivy corrupt Holly on her own however? No, if Lena doesn't encourage Holly or chooses to mind her business it doesn't work, Holly also requires Lena's reassurance
3) Is Ivy's opinion more important to Holly than Lena's? No, Holly does what Lena tells her to do for the most part, easily stopping any corruption that was in the process.
But even if they are a fundamental prerequisite for Holly to go through any kind of change, I wouldn't call Ian and Lena's influence in getting Holly out of her shell to be a "corruptive" one if all they are doing is offering different perspectives and trying to support her with her self-esteem issues. They might leave her in a more influenceable state but I wouldn't call that "corruption" until they start pressuring her in the same way Ivy does. I do agree that in the scenarios where Lena leases her credibility to Ivy's plans that in some degree she is responsible for Holly's corruption, even if she wasn't the architect behind it.
Jack gets a bit more shady if you play the scenario where Ash cheats on Eric with him early on but then regrets it and tries to stay away from Jack. He starts being more pushy with arguments like she's just lying to herself, that she felt more alive with Jack than she does with Eric, etc etc. I agree he isn't so bad if you play an Ash that keeps to her boundaries with him from the start or an Ash that gives herself fully with no regrets, but we really don't know how things played out with Eva to say he didn't do some manipulation, which he is very capable of doing.I'm just projecting his interaction with Ash to Eva because I doubt he'd treat them all that differently. With Ash he didn't really resort to any coercion or manipulation. He was obnoxiously flirtatious, asking for selfies, and sending unsolicited dick pics, sure, but it's a creepy asshole behavior, not really manipulation. He probably made Eva drink a lot just like he wanted to do with Ash, and then he kissed her. An asshole move, but after that interaction Eva was free to avoid him like a plague if she was really a "good naive girl that fell into his trap". No, the next morning she defends her behavior and basically says YOLO, having no regrets or second thoughts, and even gets mad at Ash if she doesn't enable that behavior. Jack probably said to Eva that it wasn't a big deal to cheat on her boyfriend, but it's straight-forward seduction move which wouldn't work on a girl who wasn't already thinking about cheating so I don't think he really corrupted Eva. If it was all him, at worst she could believe that she was having an affair with Jack, which would stroke her ego, but then she starts flirting with creepy thugs and even fucking them for no other reason than thrill. Who told her that it's okay to be promiscuous? Nobody did, she simply got hooked to the freedom that the cheating lifestyle offered her and she had no intention of stopping, becoming more eager and curious to try the shady stuff. If Jack started a spark, Eva herself kept blowing at the fire and going against her old moral principles.
Also it is really difficult to make a serious character analysis of Eva, like I said she's very malleable. With relatively few interactions from the player she can range from loyal girfriend to Dave, to Ash's lesbian waifu or hardcore submissive, to BBC addicted quasi-bimbo, to junkie cumdumpster of a bunch of gangsters, etc. I don't think you can say all of that was always in her from the start like Jack tries to argue, maybe she's just not a very cohesively written character, or at best her insecurities made her very influenceable by whoever happened to be in a position to manipulate her. Also to be clear none of this is meant to be an excuse for Eva's cheating and other terrible things she can do, being weak-willed may be a cause for a lack of moral integrity, but it is not an excuse.