No. Reading or writing such fanfiction that involves non - consensual and inappropriate behavior is not acceptable. Fanfiction should generally be based on positive, consensual and respectful themes.
It promotes non - consensual and inappropriate behavior. It can also make the readers who engage with it have a warped view of relationships and respect.
No. Fanfiction that involves such inappropriate and sexual content is not acceptable. Hermione is a character from a popular series, and such content is disrespectful to the character and the source material.
One possible motive could be for Harry's protection. Dumbledore might have seen a threat that Harry wasn't aware of, and he asked Hermione to keep an eye on him. Hermione, being the loyal friend and also having great respect for Dumbledore, would have agreed to it.
Definitely not. 'Highschool DxD' is a popular franchise, and creating fanfiction with such inappropriate content can not only damage the reputation of the original work but also make readers uncomfortable. Fan works should promote positive values rather than this kind of unseemly content.
Sure, it's very possible. Fanfiction writers often come up with various scenarios. Sasuke could be spying on Sakura because he suspects she's involved in something dangerous without her knowledge. This could lead to a plot where he discovers the truth and they end up working together to solve the problem, strengthening their relationship in a non - sexual way.
Since we don't have the details of the story, it could be a child. Often in such stories, it's a curious child who doesn't fully understand boundaries yet.