Personally i'm one of those people who see
Riley as more of a boys name and dont like boys names in general given to girls, BUT i think its important to use names you love.
Ryleigh is way worse to me than
Riley.
Rylie or
Rylee could work.
I was actually wondering the other day how about adding to
Riley?, like Riliana/Ryliana (ry-lee-anna,
Riley and
Anna) nn Riley/Rylie. Would combining
Riley with another name ruin the name for you?
Anyway, my other thought here is
Riley needs a girly feminine middle name.