Thanks! I thought about having that instability in this game. However, as I worked on the game more, I found it wasn't really my narrative style and decided to just have the varied endings instead. Plus, the pre-established backstories of the characters would have made ambiguity difficult. I think it worked out fine in the end. Like you said, Mokou and Kaguya's relationship means a lot of the endings could have happened along one timeline.
I plan to make some more IF games. Hopefully I manage to finish another one soon!