You will play as all 3 characters in the final drop. You go in this order:
Yuri, Ren, Yuri, Miu, Ren, Miu(cutscene) and then Yuri. Yuri has 2 endings, Ren has 4 endings and Mui has 2 endings.
You can replay this chapter on very easy and speed run it in about 20 minutes.
Miu's endings:
A more points, take the final photo at the beach
B dont take the final photo at the beach
Ren's endings:
A1 choose the photograph and touch Oso
A2 choose the photograph and take 2 photos of Oso
B1 choose the hair and fight MORE POINTS
B2 choose the hair, take no photos and get dragged into the box
Yuri's endings:
A defeat the boss in the first phase/underwater and touch her
B defeat the boss, go to second phase/above water, defeat her again and then touch her
For Ren's B2 ending, it will take a few tries. Stand near the box. Dodge the dolls if you have to. I think it is ok to photo the dolls if you have to.
If you are going for all achievements, keep this in mind:
-to unlock a special lens, you have to beat the game with both of Yuri's ending while wearing the white kimono. To get the white kimono, you have to beat the game at least once.
-if you are going for an S+ ranking, the Yuri's boss fight can go on as long as you like.