Well, I thought I would throw in my two cents about the blackmailer thing with my own theory. I believe that the blackmail is the start of a scheme with a darker undercurrent than most have realized yet. It all has to do with conditioning. Let me explain.
I must admit, when I initially played through, the idea that the blackmailer was Delilah was so ingrained in my head that I couldn't get it out. I no longer believe that, but at the time there was WAY too much evidence that it was her. That includes that Ashe ran into her on the bus outside the gym, a place where there are known to be full body mirrors, which if she was spying on Ashe she would have known,
Another fact that I haven't seen mentioned yet is the change in her nail polish color at that time she met Ashe on the bus. All the previous times her nails are shown to be a soft pastel rainbow of colors, yet on the bus they are shown to be purple, white, and green. That may not seem like much unless you are paying attention to the themes underlying some of the social interactions, and their real world counterparts. If you are, then those colors are very familiar to you.
After that she hid her phone against her chest and quickly slid it into her purse, making it obvious she didn't want Ashe to see what was likely her picture. The fact that she then did an awful job lying about how she found out cemented it. I think these are red herrings now. See, I was convinced it had to be someone that was at the sleepover, or else how would they have seen Ashe to know. I even found myself examining Delilah before and after Ashe and Zoey slipped away to see if there was any indicator it was her.
I am aware about the theory involving the data hacking, but there's not been any indication in the game that this is what is actually happening here. There is evidence it is happening, but there is also evidence that this is a more straightforward plot. I read on here the theory that it could be Victoria, which I initially dismissed, but it stuck around in the back of my mind and kept bugging me until certain pieces fell into place and now I see it as the most likely option.
It actually started with Mrs. Leone, the math teacher. She mentioned that she and her wife were getting divorced, which Ashe relayed to Kate and Evelyn at the kitchen table. Kate responded talking about how it must have been bad to risk the Goddess's wrath with divorce, and then mentioned that some people “Shame others and then do the exact same thing behind closed doors”.
The fact Kate then mentions her wife's “business trip” in quotes is indicative that she, in fact, has her doubts. I think Victoria has been dropping subtle clues and hints lately that she's having an affair. Whether she is or not is irrelevant, although I think she actually is, as bore out by the Kate quote earlier. I think the clues have been just enough to make Kate suspect, but not enough to prove anything. That way, Kate can't use the evidence against her, but is so frustrated and angry she is likely to go out and cheat herself to get revenge. I think that was Victoria's initial plan.
Now, how could Victoria be the blackmailer? Well, if she was dropping hints about an affair, and had installed a secret camera in the bedroom, it would be for one purpose and one purpose only: to catch Kate having an affair herself on film. I think the camera may be one of those with motion detectors and automated alerts. That way, when it went off really late, Victoria got excited and thought it had finally happened, so she checked. Then she saw Ashe, and saw that Ashe is a duplo, which gave her a new idea. Not only could she catch her wife in an affair, but one with a duplo? That would be 10 times as bad.
I mentioned conditioning, but what did I mean by that? It's the same way you train a dog. You give them something small, then something more, continue until they are doing what you want when you issue a command. There is a small similar situation, though in some ways not as extreme, happening with Natasha, even more on Kitten path. She is slowly getting Ashe accustomed to the idea of obeying her, and slowly turning up the pressure she's exerting. Oh, and before anyone starts saying something, I honestly believe if Ashe had, even once, given her a firm and convincing no, she would have stopped. It might have meant Ashe had to face the consequences of stuff, but it would have been over. However, it seems obvious that there is some part of Ashe that likes it. She even comments to herself about how she's confused that she does.
Anyway, that's what the blackmail is. So far, there have been 4 events, 3 of which happened on the same day. The picture in her underwear, the plug, the photo of the plug, and sleeping with Vanessa. These are all slowly building, much like the frog in boiling water analogy. Slowly turn up the temperature. The first one was to get her accustomed to obeying. No worse than a bikini pic. No big deal.
It's the rest of them that take on a more sinister undertone when viewed through that lens. The plug isn't just about the plug itself, it's about showing Ashe that her body is no longer in her control, and the blackmailer can make her do things with it whether she wants to or not. The photo for proof, however, I believe serves a dual purpose. First, it is for proof, and to force Ashe to take a photo of herself pushing that boundary farther. Second, I believe it is meant to be used in case Ashe refuses to follow the tasks. That way Victoria doesn't have to rely on the photo from the camera, and can keep it a secret just in case she needs to keep it for when Kate does eventually cheat to get her back. There's also the fact that Rachel mentions that as long as she doesn't send any actual photos, then the blackmailer has no proof, which to me helps solidify this as a reason for it.
The final one though, sleeping with Vanessa, is what clinched it in my mind. This isn't just teaching Ashe to follow orders with her body, but an attempt to condition Ashe to the idea of seducing a woman on command. We already know that Delilah wanted to have another sleepover, which would be the perfect time if Ashe was to get a message to seduce in Kate in her own bed before morning. This would also explain why Delilah is acting so weird. She's torn between two people she cares for, and is going a bit crazy because of it.
However, why would Victoria go through all of this? I think the answer is in their society. It is obvious that the church has a HUGE impact on their daily lives, and is a massive influence on marriage obviously, so they might even have some control over who can divorce and, more importantly, why. Additionally, in some places, even with no-fault divorce infidelity can affect alimony and asset distribution. If she was the party at fault, the courts and or church might weight that against her and award Kate more. If Kate if at fault, they may award her less.
It would also remove the obvious stigma for Victoria. If she was the victim, then no one would be able to blame her when in a couple months she starts openly dating someone else. So, I think this is all a giant divorce scheme to try and keep more of her assets and income to have a better start for her and her new girlfriend, if there is one. Is there a possibility it's someone else? Of course. It could actually BE Delilah or someone else entirely. But this makes the most sense to me.
Also, on a side note, I have seen people thinking that the girl at the end is referring to ruining Ashe's life, but I honestly believe it's Vanessa she's after. There are 7 visible packages of the Elysium on the table, which at the OLD price for spike would have cost $1,050, but that price went up. So, assuming the max is that it doubled, that's between $1,050 and $2100 dollars of Elysium that she plans to throw away just to fuck up the party. That definitely sounds more like a Vanessa enemy than an Ashe enemy to me.
Anyway, sorry for the wall of text, but I had a few thoughts.
