Is it possible to prevent Susan from going missing or at least find her?
it's part of the main story, your chosen "waifu" will go missing. Rest of the story isn't done yet and I imagine given their track record and how they're making money from patreon, they're not going to finish it in the next few years at least
Nope, but if you play in new plot, she (or any other prefects) will return in next chapter
