I'm going back to these ideas, based on the Pixil requirement and some of the good points made by other members of the group:
Personally, I would only add, for greater morbidity, that Sophia reaches orgasm less, because of her shame and humiliation, with looks of permanent disgust on her face, at being forced to do all of this. Also that it shows in her gestures that she has finally been defeated and totally dominated by Aiden. And perhaps, as an element of intense humiliation for her and fabulous pleasure for the three boys (Aiden and his henchmen), it is not Darius who must first see her completely naked, but rather that she, when she is led by the neck to Aiden, must tolerate that Aiden himself, in front of his friends, removes her clothes one by one, leaving her only with her socks and shoes, and before taking her with the students, the 3 of the band finally have the long-awaited first prize, which is groping her and sucking her tits without her being able to avoid it, or holding her by the arms, which is an excellent resource that you added. Otherwise, great where the story is going. Under no circumstances should that damn Dylan arrive as a "savior"... at least for several more chapters... I think that this fourth part actually has nothing of "Last Task", but rather the beginning of the Aiden's total dominance over Sophia. Not necessarily she will "transform her mind" as she will continue to be a teacher and enduring leers from Aiden and André in class. Then, of course, there will be permanent shows, she will earn money, all the henchmen of Aiden's gang will enjoy seeing her undress in front of them, and Aiden will fulfill his initial promise that he made to all his friends... And so on... there is material for quite a few episodes, before some inappropriate asshole comes to "save" the beautiful teacher LOL
You can also take advantage of the resource that Aiden's uncle is an obscure (but successful and cheating) lawyer, with which Sophia's "end of extortion" and "beginning of a new career" must be certified with the signature under pressure of a work contract at the club, with limited hours and setting conditions and demands that she must abide by during her working hours. In fact, it would be great if Aiden totally stripped Sophia (the device that he can shamelessly get his hands on her and strip her when he wants, I think is very interesting, since it establishes with definitive clarity who is the boss in that bond ) and she attends the club office, along with Aiden and Aiden's uncle, to sign the agreement, while she is naked.
I believe that, so that it does not lose a minimum of argumentative realism, we must not forget that, for more "villains" and delinquents are Aiden and his gang, finally they are very hot teenagers for a while with the teacher Parker.
So, the BDSM sophistication with torture, I personally would not expand it too much, I think they will first seek their humiliation and pleasure through the exhibition Finally! of a total nakedness of Sophia before them, and small revenge: Sophia has repeatedly told them to keep their dirty hands off her. Well then, Aiden will get his hands on her and he should personally strip her naked in front of the rest, so Sophia understands who's boss now. And don't forget the bottom line: Before expanding Sophia's new forced labor role, signed contract and all, before fulfilling the dream of ALL of Aiden's gang members, plus clientele in general, in such a way that good part of the male population of the city will gradually get to know her, naked Sophia, we must not forget the essential thing: The next step is for Sofia to dance naked and endure being fully enjoyed by the three gang members... and that that butt plug, only , is withdrawn by Aiden, who will reserve the final dessert for himself: enjoying Sophia from behind, "showing" his cronies how to fuck her ass without haste. That is a pleasure reserved for a true "boss" who "shows" his charges how things are done.