Nate could also be a good choice, but instead of the typical toxic relationship, you could write a fanfic where they both go through character growth and end up having a more healthy and respectful relationship. It would be a great way to explore their characters in a different light.
One idea could be exploring Maddy's dreams and ambitions outside of her relationships. Maybe she has a secret passion for fashion design and is working on her own collection in secret.
In the 'dave perez big story', Dave Perez could be an activist. He might have fought for an important cause, like environmental protection or social justice. His efforts and the results of his actions could be what the 'big story' is all about. He could have led protests, lobbied for new laws, or started initiatives to bring about positive change in society.
The Cullens as a whole would be cautious. They would be worried about the implications of a half - werewolf, half - human (with a connection to vampires) baby. They might offer their help and protection, but also keep a close eye on the situation.
Bella would be heartbroken. She has put so much trust in Edward, and this act of cheating would make her question everything. She might become angry and lash out at both Edward and Tanya. She could also become very sad and isolate herself from others.
I haven't come across a 'girlpenis bella twilight fanfic' myself. Fanfic communities cover a wide range of themes and interpretations, but this one might be quite unique. It could also be that it doesn't exist at all, or if it does, it might be in a very niche part of the Twilight fanfic world. Try looking on popular fanfic websites and use specific search terms to see if you can find anything related.
Some popular 'Twilight Edward and Bella Fanfic' include 'A Glimpse Beyond Twilight'. This fanfic gives readers a chance to see what could have happened after the events of the original series. 'Edward and Bella: Unseen Moments' is also great as it reveals some of the unshown moments between them. 'Twilight Fanfic: Edward and Bella's Love Redefined' is another good one, as it redefines their love in a more complex and interesting way.
One great fanfiction could be where Edward and Bella's relationship is explored more deeply in a different vampire society setting. For example, they might be in a vampire clan that has unique rules about human - vampire relationships.