For Ayumi, it mostly has to do with her grades. Have her fail the test and try it, she should accept then.
I see where the problem is.
I haven't downloaded the hotfix, which solves this problem. LOL
Some constructive criticism I think would help: I would however recommend putting in a questline system that directs you in the right direction for each student. Maybe even just a hint in the gallery menu for each scene. Because now at this moment i have run through the game 1000x times because i don't know which scenes exactly lead to which outcomes for the various scenes if you get what I'm saying. I don't know how realistic that would be to implement, but just a thought. :)
I love the game so far. Want to explore everything it offers. Keep up the good work