Thor would be one of the active ones. He has a lot to share from his Asgardian experiences. Hulk, well, he might not type much but when he does, it would be in short, powerful statements. And Scarlet Witch could be in there too. She could use her powers to sense if there's any danger approaching the chatroom or the Avengers themselves while chatting with the others.
The plot might involve a new villain who hacks into their chatroom. So, the Avengers have to figure out how to stop this digital threat while also communicating within the chatroom to coordinate their efforts. They could be discussing their individual strengths and how to use them against this new enemy. For example, Captain America could be leading the conversation on strategy, while Black Widow provides intel she's gathered. Hulk might be there just being Hulk, with the others trying to keep him calm and on track. And all of this happening in the unique setting of a chatroom, which adds a modern and interesting twist to the typical Avengers story.
Captain America is very likely to be featured. He has that paternal, moral - compass kind of vibe. He would be the one to gently tickle the 'daughter' as a way of showing his soft side. Thor could also be a popular choice. His big - hearted and sometimes child - like nature would make for some great tickle - related antics with the 'daughter' figure.
Obviously, the main Avengers like Iron Man, Captain America, Thor, Hulk, Black Widow, and Hawkeye would be the main characters. They are the core of the team and any story about the Avengers, drunk or not, would likely center around them.
Captain America could be a likely character to be betrayed. He represents the old - school values of the Avengers, and in a more modern, cynical world within fanfiction, some might see his ideals as outdated and turn against him. Also, Tony Stark. His wealth and sometimes over - confident attitude could make some of the other Avengers, especially those with more humble backgrounds, feel resentful and potentially betray him. And Thor, being an Asgardian, might be betrayed due to the other Avengers' mistrust of his alien nature or the potential threat Asgard could pose.
Captain America and Peter would also have great interactions. Steve Rogers could teach Peter about the importance of responsibility and leadership. And Peter, with his youthful enthusiasm, could remind Steve of the good in the world and the future.
Tony Stark could also be a key figure in some fanfics, even though he's no longer alive in the main MCU timeline. His intellect and previous experiences with multiversal - related events (like in Endgame) could be explored in the fanfic. Maybe the Avengers find a way to access his knowledge or even a version of him from another universe to help them out.
Captain America is a likely candidate. He has a strong moral compass and a sense of protectiveness. He would see it as his duty to take care of the baby. His old - fashioned values would make him a great caregiver, like making sure the baby has a proper upbringing even in the middle of all the chaos in the Avenger's world.
Black Widow. She has a lot in common with Batman in terms of skills. Both are highly trained in combat, stealth, and espionage. They would understand each other's need for secrecy and their ability to operate in the shadows.
Hulk. He has a tendency to lose control and his large size could easily knock over shelves or accidentally break items.
Vision could also have an interesting interaction with Bucky. Vision is an android with a unique perspective on life and morality. He might be curious about Bucky's past as the Winter Soldier and how he is dealing with his regained humanity. Their conversations could be really thought - provoking, exploring themes like what it means to be human and how to atone for past wrongs.