Captain America would probably be very reflective. He might see his past self as a reminder of his long journey and how much he has changed. He could try to offer some words of wisdom to his younger self.
Their interaction would be very interesting. They would probably be very curious about each other. The present - day BTS might want to give advice to their past selves, like how to deal with stress better during their early days.
Well, they might be shocked at how far they've come. Maybe their past selves would be in awe of their current achievements. For example, seeing the huge stadiums they now perform in compared to the small practice rooms in the past.
The answer to the question that humans would travel to the past and meet their past selves in the future was not absolute because there was no scientific evidence to prove this. However, according to some novels and science fiction works, humans might encounter their past selves in the future, but this depended on many factors such as whether the technology of time travel was available, whether the time they traveled to the past was close enough to their past selves, and so on.
In some novels, humans travel back in time to meet their past selves. These plots often involve some mysterious scientific principles such as "time tunnel" or "time warp", which may allow humans to travel through time and meet their past selves. But in reality, we currently have no scientific evidence to prove this possibility.
In short, it was still unknown whether the future could travel to the past and meet the past. More scientific research and evidence were needed to confirm it.
No way. The manga portrays their connection through mutual respect and competition in their journey to become great heroes. A kiss is not part of that narrative at all.
A possible plot could be that the meeting causes some sort of time rift. The Avengers then have to fix this rift while also dealing with the differences between their present and past selves. Their past selves might be more naive or idealistic in some ways, which could lead to both comical and tense situations.