Thor would be a bit more straightforward. He'd probably see the Spider - People as brave warriors. He might be a bit confused at first about the multiverse concept but would quickly accept it. He'd be like 'These small heroes have great courage, much like the warriors of Asgard.' And he might offer to train them if they ever met. He'd also be entertained by the humor in the Spider - Verse, like the interactions between Peter B. Parker and Miles.
The plot might involve the Avengers seeing the multiverse aspect in Into the Spider - Verse and realizing the vastness of the universe. They could then start to look into the possibilities of other multiverses and if there are other versions of themselves. This could lead to a whole new adventure where they try to contact or visit these other universes, all inspired by what they saw in the Spider - Verse.
They often react with shock and grief. Some might immediately go into a rage, seeking revenge on whoever caused Spider - Man's death. Others may be paralyzed by the sudden loss, unable to function for a while.
Spider - Man would likely be confused at first. He respects the Avengers and can't understand why they are suddenly after him. He might try to talk to them, to explain that he's innocent. For example, he could swing up to Captain America and start pleading his case.
Spider - Man would probably be shocked at first. He looks up to the Avengers and being kidnapped by them would be the last thing he expects. He'd likely try to talk his way out, using his quick wit and charm. He might start by asking why they're doing this and try to convince them that they've made a mistake.
Spider - Man would be very confused. He would feel betrayed because he thought the Avengers were heroes he could trust. He could start by asking them why they are doing this. If they don't give him a satisfactory answer, he might try to escape in a sneaky way, using his spider - like abilities to find a weakness in their capture setup while still trying to reason with them.
Spider - Man would probably be defensive at first. He's used to working alone most of the time, and being interrogated by the Avengers would seem unfair to him. He might crack some jokes to ease the tension, but also firmly state that he's a hero too.
The Avengers would be very concerned. Captain America would immediately take charge of the situation, trying to keep everyone calm while they assess Spider - Man's injuries. Iron Man would start scanning for the best way to treat him, using his high - tech equipment. Thor might offer some of his Asgardian knowledge of healing, if there was any. Black Widow and Hawkeye would be on guard, making sure there were no further threats while the team focused on Spider - Man.
Their dynamics would change a great deal. There would be a lot more tension. Some members might blame themselves or others. For example, Iron Man could be at odds with Captain America if they had different ideas on how to handle the situation. Their usual teamwork might break down as they are all dealing with grief in different ways.
One idea could be a story where Miles Morales has to team up with an alternate version of himself from a dimension where he never became Spider - Man. They have to overcome their differences and learn from each other to stop a new villain that is threatening all the spider - verse.