Her relationship with her team would likely become more complex. They might start to notice that she's different, more powerful and a bit more secretive. For example, Nora might be a bit hurt that Pyrrha doesn't share her new situation with her right away. Ren, on the other hand, would be more understanding but still concerned about the potential danger it brings to the team.
The team might initially be in awe of Pyrrha's new powers. But as time goes on, they would have to adjust to the fact that she now has a greater burden. Her relationship with Jaune could also change. He might be even more protective of her, while she might be more hesitant to let him get too close in case her enemies target him because of his closeness to her as the Fall Maiden.
If they time travel, their relationship could become stronger. They'd be relying on each other in a new and strange situation. Having to face the unknown of a different time period would make them depend on one another for support, both emotionally and in terms of survival strategies.
I think Ruby could be the most likely. She has always been at the forefront of the team, with her leadership skills and strong will. Her silver eyes already give her an edge, and as a Maiden, she could use her speed and new powers to protect her friends even better. Also, her innocent - looking exterior but strong - hearted interior would make for an interesting contrast with the powerful Maiden powers.
With Yang, their relationship would likely be less of a sisterly, protective one. Since Goodwitch would be in a parenting role, Ruby might not rely on Yang as much for protection. Yang might also see Ruby as more independent and grown - up, which could lead to a more equal friendship.
A possible plot could involve Pyrrha having to face off against other powerful characters who want to steal her Maiden powers. She would have to use her combat skills, which she's already known for, in combination with her new Maiden abilities. Maybe she teams up with some unexpected allies, like a group of outcast Huntsmen who have their own reasons for wanting to protect the Maiden powers.
There would also be a shift in their dynamic. Instead of just being an acquaintance or someone she looks up to in a way, he would become a parental figure. This could lead to some interesting conversations. For example, Qrow might start giving Weiss advice not just on fighting but also on life and how to deal with her family issues. He could share his own experiences growing up and how to handle the pressure of being part of a powerful family like the Schnees.
She would likely be consumed by guilt. It's a feeling that would be ever - present, constantly reminding her of what she has done. Every little memory of her team would be like a stab in the heart.
If Olivia is pregnant in fanfiction, her relationship with Fitz could become more strained. Fitz, being a political figure, might worry about the scandal that could erupt if the pregnancy becomes public knowledge. He could try to distance himself from Olivia to protect his own political standing.
Their relationship would likely become even more intimate. Ty would be extremely protective of Amy during her pregnancy. He might take on more of the physically demanding tasks at Heartland so that Amy can rest. They would also have deeper conversations about their future as parents and how they want to raise their child in the Heartland environment.
With Weiss, their relationship could be more strained at first. Since Weiss has some preconceived notions about Faunus, she might be initially distrustful of Ruby. But as time goes on, they could overcome this. With Blake, they might bond more deeply as they both share the Faunus experience in a way. And with Yang, Yang would be very protective of Ruby, especially if Ruby faced any discrimination because of being a Faunus.
If Ruby turns into a Grimm in fanfiction, her relationships would be severely strained. Her friends in Team RWBY would be confused and scared at first. Weiss might be especially distrustful, given her family's views on Grimm. Blake, who has her own history with being an outcast, might be more sympathetic but still cautious. Yang would be heartbroken but determined to get her sister back to normal.