Noticing a lot of Twos in Requiem

There's a lot of duos in the game, I'm noticing. Siblings or just close friends/allies, but always in twos. Leon and Grace, The Chunk brothers, the Singer sisters, the clones Marie and Emily. There's even 2 Chefs. All share a similar path with their counterpart. I don't know if it means anything to the story, but it definitely stands out as a central theme to character building in Requiem, or at least, in most part, the character building in the Rhodes Hill Care Center.

Are there more duos I'm missing in Requiem that anyone else can think of? What do you guys think about what it has to do with the story?