Hi there! Generally it comes down to working with player's preferences and talking it out if need be. We're generally chill and flexible. For the example you provided, the Junko player is actually fine with other characters being aware of the spoiler regarding her, and so no one's had to worry about apping characters from canon points where they are aware of her true nature. I don't foresee any trouble with Rantato canon point wise, especially as our Kaede is from the end of Chapter 1. I can get in touch with the players in question to make sure!

And you're welcome!