The Avengers as a whole would probably start to work with Daredevil more closely. They would realize that his blindness doesn't make him any less of a hero. They would also learn from his unique fighting style which is adapted to his lack of sight, and they might incorporate some of his techniques into their own combat strategies.
One possible plot development could be that the Avengers initially doubt Daredevil's abilities because of his blindness. But as they see him in action, they change their minds. For example, during a battle, Daredevil uses his enhanced other senses to detect enemies that the Avengers couldn't see or hear. This makes them realize his worth.
In a fanfic, when the Avengers find out Matt is blind, it could lead to a whole new dynamic within the group. They would start to see Matt in a different light. Some might underestimate him at first, but as they see him in action, they'd realize his blindness doesn't hold him back. His heightened senses would amaze them. For instance, his ability to 'hear' the layout of a room or sense an enemy's approach. This new knowledge would also make the Avengers more protective of Matt in dangerous situations, and they might even learn from him how to rely more on their other senses too.
They could react with surprise. After all, Peter is still young. But then they would likely be happy for him. Maybe they'd offer to take MJ out for a nice dinner to get to know her better.
Well, some of them might be really surprised. Tony Stark, for example, could become very protective. He might start making special suits for Spider - Man that are more suitable for a kid, with extra safety features. Captain America would probably be more concerned about the fact that a kid is out there fighting. He'd want to make sure Spider - Man is trained properly and not in over his head. And Hulk, well, he might not really understand at first, but then he'd probably see Spider - Man as someone he needs to look out for too.
In many fanfictions, the Avengers' reactions vary. Tony Stark might be proud, like he's found a protege. He'd probably start upgrading Peter's suit right away. Captain America, on the other hand, would be more concerned about Peter's moral compass and whether he's ready to be a full - fledged Avenger. Hulk might not care much at first, but once he sees Peter's strength, he could become his ally. Overall, it's a mix of different emotions and actions.
Bruce would probably be more analytical. He might wonder how Tony's marriage could affect his work and the team. He could also be curious about Tony's relationship dynamics. Meanwhile, Wanda might sense the emotions involved, like Tony's happiness or any underlying stress in the relationship. And Rhodey would likely be supportive, since he's Tony's close friend. He might even help Tony deal with any potential issues that come up with the Avengers' reactions.
They might be shocked and confused. It could lead to a lot of internal conflict and soul-searching among the team.
Thor could be angry. He's a proud warrior and being kicked out like that might be seen as an insult. He might even challenge Tony in some way, either verbally or physically. However, he also has a sense of honor and might listen to Tony's reasons if given the chance.
Well, some of the Avengers might be shocked at first. Tony Stark could crack a joke about it to ease the tension, like 'Loki, you sly devil, when did you find the time for kids?'. Captain America would probably be more serious and concerned about what this means for the safety of the world, seeing Loki as a potential threat through his children. Thor, on the other hand, might have mixed feelings. He loves his brother despite all his wrongdoings and might be more open to getting to know his nephews or nieces.
They might be a bit surprised at first. Maybe Tony makes some jokes about British tea and bad teeth, but in a friendly way. Steve would probably be intrigued by Peter's different cultural background and might ask him about British history.