One way this could be possible is through some sort of time - travel or alternate reality mix - up. Maybe in a universe where the normal rules of genetics and relationships are bent. For example, if there was a powerful magic or technology that rewrote the fabric of reality, it could make Tony Stark be Steve Rogers' son. It would completely change the dynamics of their relationship and how they interact with other Avengers.
It might also change the dynamics of the superhero community. Other heroes could see Steve and Peggy starting a family and be inspired to think about their own personal lives. Or, they could rally around to protect Peggy during her pregnancy, making it a unifying factor among the heroes.
Yes, in certain Steve Rogers fanfiction, he can be abused. Fanfiction writers often take creative liberties and may subject their characters to difficult situations. Some might do it to show how he overcomes adversity even in extreme circumstances. But it's important to note that this is not representative of all fanfiction about him. There are many stories that are more light - hearted and focus on his relationships and adventures in a positive light.
Steve Rogers' death has been depicted in the comics. However, comic universes are complex and his story can be revisited or reinterpreted in different ways.
Steve Rogers' height in the comics is kind of fluid. Sometimes he might be shown a bit taller or shorter, but on average, he's thought to be about 6 feet. It's not a hard and fast measurement and can change based on the creative direction of the particular comic.