I'm pretty sure there is a secret handshake to the bookends among us, an indistinguishable call between engine and caboose. A wink and a wag between head and tail. He came first and she came last and it's all part of the plan they made when they were back behind the scenes.
Rock, paper, scissors, Archer's turn. And then Fable's. And then Boheme and Reverie tied and both got scissors at the same time. And then rock. And then paper. They tied so they both came through the curtain together, and then at the last moment, Bo picked paper and Revi picked rock and their birth order was decided. Six years and four months separate first from last. Three dozen inches. Thirty something pounds. Archer's the tallest and Revi's the smallest but lying down they're all the same height.