1.) Still include them! If they’re part of the story in some way, even if you haven’t gotten to that part yet, you can still include them!
2.) Yes! Even if they’re only mentioned in text, you can still include those characters as well! Don’t worry about including every single character either!
The question isn’t something I’m looking at in detail. It’s just for fun so I can see the range of characters that people made VNs for! :)