Ok guys I think I may have sorted out what the quest is, it took me a lunch break with the annoying (not really) tries to after dinner and it's easy to figure out without having to repeat giving Isabelle's panties or glasses:
Before you escort and follow Spinach out of the room, make sure Maxine is not around. I was halfway there but she popped up sleeping on the entrance hall couch. You also need to check the admin wing if she's dangling with her binoculars, as well as upstairs investing the vending machine. These are 3 integral spots Maxine will always be, as per any quest with characters in the background, the best thing to do is do it in advance, go up/down/left/right.
By halfway I mean she makes it to the principal's office, but before Spinach does a 180 heading back, make sure Maxine is not sleeping at the couch, or she'll find her kitty cat if it goes upstairs. While upstairs near the vending machine, do good use of the game's mechanics of scrolling back and forth (which is the time bug?) to check if Maxine is ever around. If she's not there, keep interacting with Spinach until you both meet Isabelle where she picks the cat up. Then you hand back her glasses/panties to her, brief talk and you both end up back in your room.
Then the rest is history ͡° ͜ʖ ͡°, I hope you frustrated folks will figure it it out!
(Regardless of who sends/writes that email, pick "That's enough, Isabelle" if you want to get her to make a move on you instead of "You're right--negotiations are over. It's time for justice." otherwise you'll get no sex!)
