In fact there are several if you don't go the crazy Yandere route you will never ever unlock Camila, with Bree you open 2 girls who are Kat in the game Route and the normal one that opens Reona, you must farm her yes or yes, with Sasha if you don't farm her well you can lose the band harem and even the house harem, another one that is a pain in the ass to do is the Palla route, tedious and boring that takes so much time that it is better to start it from the beginning of the game and not even then you want to finish it.