I don't have enough information to say exactly who Tara Reade is in these stories. She could be an ordinary person with an interesting story, or she might be a public figure in a specific community.
One common theme is the struggle between good and evil. Since Tara is often portrayed as a good character in the Buffyverse and vampires are typically associated with evil, the fanfictions often explore how Tara deals with the vampire elements, whether it's fighting them or trying to understand them.
One popular Buffy Tara vampire Tara fanfiction is 'The Magic Between Them'. It delves deep into the relationship between Tara and the vampire elements in the Buffy universe. It has great character development and some really interesting plot twists.
Sean's feelings for Tara were complicated. He had cared about Tara and fought with his father to protect her, but he was also the only one in the family who dared to fight against his father. However, he would also abuse Tara when he felt her resistance and hurt her with violence. Even so, he would apologize to Tara and persuade her to fall into a cycle of self-doubt after hurting her. Sean's actions had hurt and frightened Tara, but it had also inspired her tenacity and unyielding character. Therefore, Sean's feelings for Tara were complicated and contradictory.
There's no information given about who Tara is reading the story to. It could be for herself, just for the pleasure of reading. Or she might be reading it to a younger sibling, a child she babysits, or even to a group of students if she's a teacher.
If these 'tara ghost stories' are part of a local folklore, they could be popular within that community. For example, if Tara is a small town, the locals might tell these stories to tourists or around the campfire to create a spooky atmosphere. However, if they haven't been widely spread or promoted, they might not be popular on a larger scale.
The truth of the Tara Reade story is highly contested. Some believe it, while others have doubts due to various factors such as lack of conclusive evidence or political motivations.