Hermione would probably be very confused at first. Snape has always been a rather intimidating and strict teacher, so his sudden change in behavior would be quite a shock. She might initially think it's some sort of trick or test.
She would likely be cautious. Given her logical mind, she would not be easily swayed by his advances. She might start to keep a closer eye on Snape's actions and motives, perhaps even researching if there are any potions or spells that could cause such behavior. If she started to feel any attraction in return, she would be conflicted because of the ethical issues involved in a relationship with a teacher.
Perhaps Snape is under a spell that makes him act this way towards Hermione. He starts to give her special attention in class, praising her more than usual and even asking her to stay after class for 'private tutoring'. Hermione, on the other hand, tries to figure out if this is really Snape or if there is some dark magic at play. She may start to investigate, which could lead to an adventure of sorts as she tries to break the spell if there is one.
Hermione is a strong - willed and intelligent character. In this fanfiction scenario, she might first be a bit amused by the Weasley boys' attempts. But as it progresses, if she senses that it's becoming a real issue, she would take control. She would remind them of their friendship and how important it is not to ruin it with inappropriate behavior. She may also use her academic knowledge as a shield, for example, by getting deeply involved in her studies and using that as an excuse to avoid the boys if their advances become too much.
Snape would probably be quite surprised at first. Hermione is known for her academic prowess and self - sufficiency. His reaction could range from being dismissive, thinking she should be able to solve her own problems, to being intrigued by the nature of her request. If it's something related to the dark arts or a mystery in the wizarding world, his interest might be piqued, but he'd still be guarded in his response. He might even try to use her request as a way to gain some advantage or information for himself.
She might initially be shocked and scared. But then she would start to think rationally and try to find a way to outwit Snape. For example, she could start to gather evidence against Snape's own wrongdoings, if there are any, so that she can turn the tables on him.
Ron would probably be horrified. He loves Hermione deeply, and his mother has always been an important figure in his life. He would be caught in a really difficult situation. He'd likely try to stop his mother immediately and protect Hermione.
Hermione may also start to scheme. She'll use her intelligence to come up with a plan. For instance, she might start to collect evidence against Snape, something that she could use to counter his blackmail. She'll research old school rules or find out secrets about Snape that she can hold over his head instead.
In some fanfiction, this can be a rather unique theme. However, it's not overly common as Hermione is often paired with other characters in more traditional fanfic scenarios. But there are always out - of - the - box ideas in fanfiction. Writers might explore this concept to add a new twist to the story, showing a different side of Hermione's character or creating an unexpected relationship dynamic.
Magic could play a role. There could be a magical spell or potion that was involved in Hermione's conception that links her to Snape. For example, a potion that alters memories and relationships. This would make for a very interesting and complex backstory in the fanfiction. Snape might not even be aware that he is Hermione's father at first, and when he discovers it, his whole view of her would change. He would have to deal with his feelings of protectiveness and his past actions towards her in Hogwarts.
Snape might initially be shocked. He's not one to show much emotion openly, but internally he could be very disturbed. He might start investigating what happened to Hermione immediately, using his skills in potions and magic to try and find a cure or at least understand the cause.
Well, Hermione is a strong - willed character. She might initially be shocked and angry. She would probably start by trying to reason with Ron, using her logical arguments to show him that his attempts at control are wrong. She might also distance herself from him socially within the story's context, like avoiding spending time alone with him and instead focusing more on her studies or other friends.