Harry would be extremely angry and immediately rush to her rescue. He has a strong sense of loyalty towards Hermione and would not tolerate her being in such a dangerous situation. Ron, on the other hand, would also be very worried. He might start panicking a bit at first but then quickly gather his courage and follow Harry's lead in trying to free Hermione.
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.
Some boys and girls might become withdrawn. They could be afraid to express themselves around their mother after being spanked. For example, in some stories, the child would avoid eye contact and stop sharing their feelings.
Well, Thor might be a bit shocked at first. He'd probably be amused by some of the wilder interpretations of his brother in the fanfiction. Captain America, on the other hand, would likely be confused by the whole concept as it's so different from the traditional stories he's used to. Iron Man would probably make sarcastic comments about how creative the fans are in coming up with these stories.
Some of the Avengers might be really curious. Thor, for example, might be interested in Percy's relation to the sea, as he has his own connection to water with his powers. Iron Man might be a bit skeptical at first, thinking they're just some kids with strange powers. But once he sees what they can do, he'd be impressed.
He would probably be quite amused by some of his past antics. For example, his constant pranks on Iruka-sensei. But at the same time, he'd also see the pain he carried from not having his parents and realize how that influenced his actions. He might react with a bit of regret for some of the stupid things he did out of loneliness, but also be glad that those experiences made him who he is today.
They'd likely be confused at first. The settings and characters of RVB are so different from their own. But Ruby might get excited about new combat ideas. She loves new ways to fight. Yang would probably laugh at any funny dialogues. Weiss might be a bit dismissive as it's not the high - class literature she prefers. Blake could be the most open - minded, seeing potential in the different storytelling.