Am I not seeing the whole initial story?

Is more available as backstory for the story? Why do I ask this? Because everyone seems to concur that Jon has a sister named Zoe for instance. This isn't just one person's invention. There are a MASSIVE number of stories that have this "Zoe" character, and other siblings of Jon's, and other details, as if it was part of the initial story, the "And so it begins" thing. But there's no mention of Zoe in it. There also seems to be concensus that Jon's mother is a single mother, while Karyn has two parents. It doesn't mention Jon or Karyn's last names, or much about their families, in the initial seed story. Where are they all getting this from? Is there some other page I'm not seeing, some sort of FAQ that you're supposed to adhere to?