Well, perhaps Natasha and Steve fall in love during a long and arduous mission. Their relationship deepens and soon Natasha realizes she's pregnant. Steve is filled with a mix of excitement and worry. They might have to keep the pregnancy a secret from some of their enemies at first. As the pregnancy progresses, they could face some internal conflicts within the Avengers team, with some members being concerned about how a baby would affect their dynamic. But in the end, the birth would bring the team closer together as they all celebrate the new life.
I think their first interaction could occur at a superhero gathering. Steve would be the old - school hero, representing the values of the past, and Carol would be the new - age hero, with her more modern and out - there powers. They'd probably exchange some polite words at first, but then as they start talking about their experiences, they'd find common ground in their dedication to justice and protecting the world.
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.
The OC should have a unique backstory that ties into the existing Avengers lore. For example, if the OC has powers, their origin could be related to an event in the Marvel universe. Also, their personality should complement the Avengers. If they're too similar to Steve Rogers, it might be boring. So, they could be more carefree while Steve is more serious. And they should have a clear motivation, like wanting to protect the world or seeking revenge for a past wrong, that aligns with the Avengers' overall goals.
Well, it would probably shatter the relationship between the Avengers. For example, Thor might be deeply angered by Steve's actions, as he was friends with both Tony and Steve. He could seek revenge or at least distance himself from Steve. Natasha would also be in a difficult position. She might feel betrayed by Steve if she was close to Tony as well, and it could lead to a split within the team she's so desperately tried to hold together.
Steve Irwin was a wildlife expert. He was known for his enthusiastic and hands - on approach to wildlife. He wasn't afraid to get up close and personal with the animals, whether it was a huge crocodile or a venomous snake.
I don't know who Steve Crisp is in this story without more details. He could be an ordinary person with an extraordinary experience, or someone with a special talent.
On the other hand, Steve might be more understanding than expected. He knows about Bucky's past traumas and could suspect that something else is at play. So, instead of immediately resisting, he might play along for a while, waiting for the right moment to figure out what's really going on and how to help Bucky.