In this fanon, Shi Ta and Shima Shita are two different people (even though they are canonically the same person). Shi had transferred out of Akademi High, and Shima is a transfer student who transferred in on the same day.
Ryusei Koki and Mei Mio are step-siblings in this fanon; who knows if they're related canonically?
Saki Miyu is bisexual and loves Kokona as more than a best friend in this fanon; canonically, she has no crush, but who knows about her sexuality?
An OC is the leader of the Science Club in this fanon; whoever ends up as the leader canonically will be a regular member in this fanon.
There are at least six students in this fanon who will never exist in the actual game.... but of course, that much is obvious.
Riku is not Kokona's suitor in this fanon; an OC will be her suitor in his place.
Ikuto is Asu's suitor in this fanon; whoever will be her suitor in the final game will either have no crush or have a crush on someone else.
Similarly, Sora is Osana's suitor in this fanon for now; if her suitor is someone different in the final game, it will change, since, although she does ship them, the one behind this fanon isn't a hardcore Sora x Osana suitor.