Hey Kratos! Thanks man, glad you enjoyed the game and good luck with your story, to answer your questions
1) Leslie's roadmap is just between me and the team, it's not something I've shared or plan to share as I like things to be experienced as clean as I can manage for the audience. We have a plan for the family, the main story plot, endgame and epilogue - as well as notes for a good chunk of the focus girls, but those are more fluid as they're meant to be able to be played in any order so the don't need to be as rigid as the family's plot line.
2) Who knows? There's definitely a chance now that MC and Ash know about it, but if/when anything could necessitate using it again, that's to be seen.
3) Amira, Yumi, all of the non-family girls that will get their own update (we call them Focus girls) have to win a vote and then get their whole story in a single update, like how Sabrina and Brenda have gotten and Sunny is getting in v.07. Amira and Yumi and the rest of the school staff are eligible for the v.08 vote though, and that vote will be starting up soon-ish on Substar!