I like Ariadne, but it's a bit a repeat but different of Persephone, if that makes sense.
Cecelia or Beatrice would be great, or even Cecilia/Cecily/Cicely or Beatrix?
Mariella is fab but a bit flat against a Persephone.
Felix or Gregory for the boys.
Other ideas:
Zenaïde, Athenaïs, Hortensia, Philomene, Circee, Azalea, Tessalie, Aphra, Andromeda, Artemise/ia, Brunehilda/Sunhilda/Swanhilda, Wilhelmina, Coraline, Cleophee, Castille, Domitilla, Bertille, Cybele, Nimue, Cephise, Eglantine?
Ferdinand, Ezekiel, Eustace, Gustave, Octave, Nestor, Arnold, Harold, Zephyr, Rudyard, Ephraim, Basil, Melchior, Joachim, Rufus, Emil, Elzear, Gideon, Gilbert, Hector, Herbert, Isidore, Leonard, Icabod, Jovian?