I'm not sure specifically what Jeff's story is here. It could be that 'it's hot' refers to the weather, and maybe something happened between Rachel and Jeff during a hot day. Maybe they had an adventure or an argument in the heat.
Atticus and Zane are likely characters created within the fanfiction world. They could be friends, colleagues, or even rivals. Without more context from the actual fanfiction, it's hard to say exactly who they are. But they are the main characters involved in this shaving - related situation.
They are likely characters within the context of the fanfiction. Without reading it, it's hard to say exactly who they are. They could be original characters created for this fanfiction, or they could be characters based on an existing fandom, like a book, movie, or TV show.
It's possible that Rachel and Will are characters from a less - known or niche media. They could be part of a small - scale web series or a local theater production that has a dedicated fan base. In the fanfiction, the writer may be expanding on the hinted - at relationship between them from the original source material and taking it in the direction of pregnancy, exploring how that would change their lives, their relationships with other characters, and their own personal growth.
Since I don't know the exact story, Rachel could be anyone. She could be a fictional character created for a novel, a real - life person that the storyteller knows personally, or just a name used in a parable.