I think Rei and Kazuha will both stay, because remember that one dream of Yuuma? He was thinking about both of them in different bodies, I think they will both stay, I'm not a mental therapist nor psychotherapist but I just think tho, on what I am saying isn't official, I feel so bad for the others I really like Mitsumi and Itsumi(;´༎Д༎`) I love themmmm
Note: Psychotherapist are not actually doctors but they can treat D.I.D( dissociative identity disoreder)
THIS IS REALLY INTERESTING