The key of On My Own
also shows helps in conveying Éponine's hope and love for Marius and her resignation to the fact he loves Cossette and not her. In The Epilogue
she and Fantine are calling to Valjean to Hevean, the lower key helps them convey that and, if I'm not mistaken, it also helps lead into the Do You Hear the People Sing?
Again, if Swift takes the part I'll be rooting for her. I don't want the musical to fail.