I decided to outline each chapter and write backstories for each of the ROs/allies of the MC from a story standpoint. There’s even the summary as you click/tap into the game.
I’m planning on my stories being fairly linear until the end (except in my Yōkai story where you either go to class or meet your parents… and then you’re either a foreigner or a native Japanese person - it’s a fact, a foreigner will have a different experience than someone born in a country) because I think doing too much branching would be tough, plus there’s also the romances. I figured some of the choices you make will influence what ending you’ll get, but most of them influence personality and dialogue/action.
I might do stat checks because for example, one of the stats is “Athletics” in both of my stories, but if I do them, they won’t happen too often. But your personality may also influence your ending 
it definitely will in the demon possession story since there’s going to be a stat that tells you whether you or the demon is winning.
Yeah, I haven’t talked about my Yōkai story. To summarize it briefly, everyone knows Yōkai (Japanese mythological creatures) exist and you’ll ally up with some of them.