Hulk could be the most surprised. He doesn't always pay attention to the subtleties of character growth. But seeing Peter, who was once a small and somewhat inexperienced hero, now be this confident and powerful figure from the future would really catch him off - guard. He might even be a bit intimidated at first by the new - found strength and presence of future Peter.
I think Thor could be really excited too. Thor loves a good warrior and Peter, with his spider - like abilities, would be an interesting addition to his view of heroes. Thor might be amused by Peter's small - scale heroics compared to his own grand battles and would enjoy seeing Peter's potential grow.
Sakura might be the most surprised. She has always been very close to Naruto, and seeing him as a powerful future version would be quite a shock. She might be amazed at how he has developed his skills and also how he has changed as a person.
In such a fanfiction, perhaps the Avengers could be shocked by how much Peter has grown and developed in the future. He might show off new powers or skills he's acquired. For example, his Spider - Sense could be even more advanced, allowing him to predict complex threats far in advance. And he could offer new perspectives on old foes the Avengers have faced, based on his future experiences.
Probably Steve Rogers. He has that all - American hero charm and he values loyalty and courage, which Peter clearly has. Steve would recognize those qualities in Peter right away and would want to get to know him better. He might see Peter as a symbol of the future of heroism and be eager to befriend him.
It could be Hydra. They might be trying to take advantage of the split between the Avengers and the Rogue Avengers. They see Peter as a wild card and try to either capture or turn him against both groups.
The Avengers might react in different ways. Steve Rogers would probably be polite but firm in getting to know Peter's boyfriend. He'd want to ensure that he was a good influence on Peter. Thor, on the other hand, might be a bit more boisterous. He could either be really friendly and enthusiastic, or his loud and powerful presence might accidentally scare the boyfriend a bit.
In my opinion, Black Widow and Annabeth Chase would make an interesting pair. Black Widow is a highly skilled spy and fighter, while Annabeth is known for her intelligence and strategic thinking. They could team up to outwit their enemies. Annabeth could learn some new combat moves from Black Widow, and Black Widow could gain insights into ancient strategies from Annabeth.
I think Captain America and Dean Winchester would be an interesting pairing. Captain America's sense of justice and old - fashioned values would contrast and complement Dean's more rough - around - the - edges attitude. They could bond over their experiences in combat and their loyalty to their respective teams.
Definitely Tony Stark. He's all about his high - tech world and order in his lab. Goose could easily get into his lab and start pawing at his precious inventions. It would drive him crazy as he tries to keep Goose away from his dangerous experiments and valuable tech. Also, Goose might short - circuit some of his equipment with its fur or just by being clumsy around it. And Stark is not really used to dealing with such unruly creatures, so he'd be very affected.
Iron Man and Batman might be the most likely to clash. Iron Man is all about high - tech and showing off his latest inventions. Batman, while also using technology, is more of a brooding, solitary figure. Iron Man might see Batman as a bit of a relic or too old - fashioned in his methods. Batman, in turn, could view Iron Man as a bit too flashy and irresponsible with his power. Their egos could get in the way of them working together initially.