The Avengers' reactions would be mixed. Iron Man might be a bit skeptical at first, thinking it could be a trick by Loki. However, once he's convinced, he would use his technology to scan Loki and try to understand the nature of the mind control. Black Widow, on the other hand, would be more empathetic right away. She has experience with mind control herself, so she would be quick to offer her insights and try to find a way to free Loki. Hulk might not understand the situation fully, but he would be ready to smash anything that gets in the way of helping Loki if the others tell him to.
Well, one thing that could happen is that the Avengers might try to find a way to break the mind control. They could consult with Doctor Strange if he's in the fanfic. Strange has a lot of knowledge about magic and the mind, so he might be able to come up with a spell or something to free Loki. Another possibility is that they try to use Loki's own knowledge against the mind control. Since Loki is smart, even when under mind control, there might be some part of him that can resist and help the Avengers figure out how to stop it.
It could lead to all sorts of wild and unexpected plot developments. Maybe Loki uses this control to manipulate Tony into doing things against his nature.
When the Avengers meet Lady Loki in fanfiction, their reactions would vary. Iron Man would probably start analyzing her, trying to figure out her weaknesses. Captain America, being the moral compass, would try to give her a chance to prove herself, but also be ready to fight if she betrays them. And Thor, he would have a mix of emotions, part anger from past experiences with Loki and part curiosity about this new form of his 'brother'. The more impulsive members like Hulk might just see her as a threat and react accordingly.
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.
In this fanfiction scenario, their reactions could vary greatly. Natasha Romanoff would likely be sizing up the situation immediately, trying to figure out how this new knowledge can be used to their advantage. Clint Barton might be a bit more hesitant as he's had his own experiences with Loki's mind - games. And Bruce Banner would be worried about the potential danger Loki's true form poses, especially if it has some kind of power that could set off the Hulk.
Some Avengers would be excited. They'd see it as a great opportunity to connect with their future lineage.
Some of the Avengers, like Thor, might have a more complex reaction. Since he is Loki's brother, he may feel a sense of responsibility towards the children. Others like Captain America would be cautious but fair, trying to assess if they are a threat. Iron Man, on the other hand, would probably be sarcastic and make some snarky remarks while sizing them up.
One challenge could be the security around Loki. His captors might have strong defenses and guards. The Avengers would have to fight their way through to reach Loki.
If Loki impersonated Thor, the real Thor would be furious when he found out. The other Avengers, like Iron Man, might initially be confused but then quickly realize something is off. Iron Man would likely use his technology to detect the impostor. Hulk might just smash first and ask questions later when he senses something wrong with 'Thor'.
Thor might be conflicted. He'd see his nephew/niece but also remember Loki's treachery. Iron Man would probably be sarcastic at first, making remarks about the family genes. Captain America would be more cautious and diplomatic, wanting to give her a chance but also being on guard. Black Widow would try to read her body language and motives right away.