you know i found out that the author shirokoi like to use song and soundtrack from anime natsume yuujinchou (its not bl or furry and although the anime is not to popular either but it's really the greatest anime for me), there is musicbox type song from opening in its anime season 6 called "floria" in sissel story, and after that there is also another soundtrack that called "Kimi ga Yobu Namae Yume no Tsuzuki" this soundtrack of piano is always great at making mystical atmosphere, well since anime natsume yuujinchou and repeat well technically had same gener(supernatural type)i can say that the soundtrack is great at making mysterious and calm atmosphere in this vn. But really i like musicbox part of floria the best i need to search for it cause i like how it's feels so relaxing when you hear it.