In the comics, Thor's daughter is Thrud. She inherits some of Thor's strength and heroic qualities. Thrud has made appearances in various comic storylines and has her own adventures.
Sure. Thor's daughter has been featured in certain comic issues. The specific roles and story arcs involving her vary depending on the series and creative team behind the comics.
In a 'bella is thor's daughter fanfiction', the plot could involve Bella being whisked away to Asgard. There, she has to learn about her father Thor and the ways of the Asgardians. She might get into trouble with the other Asgardians who are skeptical of her because she's from a different place. But as she proves herself, she could form alliances and help Thor in some great battle or quest, all while coming to terms with her new identity.
I'm not sure of a specific 'bella is thor's daughter fanfiction' to recommend. You could try searching on popular fanfiction websites like Archive of Our Own or Fanfiction.net. They have a vast collection of fanfictions, and you might be able to find one with that premise there.