Arden - generally prefer it for a girl, because my main associations with it are
Elizabeth Arden (cosmetics),
Eden, and
Arwen.
Arden Isidore Arden Isidora
I prefer
Fran as a NN for a guy (I used to live next door to an old gentleman called
Fran). It's ok for a girl, but if I had to use a NN for
Frances, it'd be Francie.