One interesting aspect could be how their relationship dynamics change. In the original, Edward was the vampire and Bella was the human, so reversing their roles might lead to a different power dynamic. For example, Bella as a vampire would have more physical strength and speed, which could make her more protective of Edward. Also, Edward as a human might struggle with his mortality compared to Bella's immortality, creating new tensions and storylines in the fanfiction.
I'm not sure if there is such a specific fanfic. There are countless fanfics out there, and while the 'Twilight' series has a large fanfic community, this particular combination seems rather unorthodox. It might exist in the vast realm of fan - created works, but it's not a common or widely - known trope within the official 'Twilight' lore.
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.
Edward's reaction can vary greatly depending on the specific fanfiction. In some, he's overjoyed right away, seeing it as a new chapter in their lives. In others, he's more cautious, worried about Bella's health and the future of their family. He could start making plans immediately to ensure Bella's safety and the well - being of the baby.
Bella might initially be terrified. She is a human being kidnapped by a vampire, after all. She could struggle and try to escape, using her wits and any available resources. However, since she has feelings for Edward in the original story, part of her might also be conflicted, wondering if there is a good reason behind his actions.
In fanfictions, their relationship is often unique due to the whole 'forbidden love' aspect. Vampires are seen as dangerous and different, yet Bella is drawn to Edward. Their relationship also has an element of mystery. Edward has a past and secrets that Bella gradually uncovers, and this journey of discovery adds to the uniqueness of their bond.
One common theme is the exploration of their love in different situations. For example, in some fanfictions, they face new threats to their relationship, like a new vampire clan that doesn't approve of their union. Another theme is the power dynamics between them. Since Edward is a vampire with special abilities and Bella is a human (at least initially), how they navigate that power difference is often explored.
Another good one is 'The Vampire's Mate'. It delves deeper into the vampire lore and how Bella, as a human, fits into their world. The relationship between Edward and Bella is portrayed in a more intense and detailed way, which makes for a very engaging read.
Love is a very common theme. Their intense, often obsessive love for each other is a central part of most fanfictions. Another theme is the struggle between Bella's humanity and the vampire world she's drawn into. Also, the idea of family, like Edward's vampire family and how Bella fits into it.