Another possibility is that it could be one of the other male members of the acapella group. It would create a lot of drama within the group dynamic, with everyone having to deal with the unexpected situation and the potential changes it would bring to their relationships.
In this fanfiction, it could also be that Becca's pregnancy is a secret at first. She tries to hide it from the group because she's afraid of being kicked out or judged. As she struggles to keep it hidden, she starts to form a closer bond with another female character who suspects something and offers her support in a really touching way. Eventually, when the truth comes out, the group has to decide whether to keep her in the group or not, but in the end, they all realize that her talent and determination are more important than her pregnancy status.
In a Pitch Perfect fanfic where a character becomes pregnant, there could be a lot of drama. Maybe the character has to balance her pregnancy with her singing career in the Barden Bellas. She might face challenges like dealing with morning sickness during rehearsals or having to adjust her performance style as her body changes.
Maybe it's a new character introduced just for this plot twist. This would add an element of mystery and new drama to the story.
It could be Ron. Since they have a relationship in the original story, it's a very likely option. Their relationship could be further developed as they face the new chapter of becoming parents together.
Perhaps it's a human boy who accidentally wandered into the fairy world. Tinkerbell, being curious, interacted with him, and in a magical turn of events, she became pregnant. This would create a lot of drama as the fairy world and the human world don't usually mix in such an intimate way, and there would be a struggle to figure out how to handle this situation.
It could be her long - time boyfriend. They might have been planning for a family in the future, but the pregnancy comes as a bit of a surprise earlier than expected.
Another possibility is that it's a result of some sort of experimental jutsu gone wrong. So there may not really be a traditional 'father' in the sense, but rather it's a consequence of Naruto's own actions in the world of ninja magic.
It could be her long - time boyfriend. They've been in a loving relationship, and this pregnancy is a natural step in their relationship journey.
It could be another hybrid like herself. Maybe there's a new character who is also part vampire and part human, and they fall in love and conceive a child.
It could be Flynn Rider. Since they have a strong relationship in the original story, it's very likely that he is the father. They are in love and have been through a lot together, so it would make sense for him to be the one.