I think you need something else unusual or nature-y. I used to have a colleague who had a little girl called Ocean. She also had a little boy - called William. Both lovely names individually but they just seemed like such a mismatch to me. They'll be be young adults now with their own identities though so I suppose the matchy thing isn't the be all and end all. It only matters for the first 18 years.
[You can be too matchy though. I'm adding this after writing my list in which I initially unthinkingly included Bay, Haven, India and Sydney. Your daughters would sound like a summer holiday together!]
How about ...
Athena, Artemis, Amberley, Ariana, Amaya, Aspen, Aven, Autumn, Avery, August, Asher, Albie, Atlas
Bronte, Briar, Blossom, Bodhi, Baird
Cassidy, Calliope, Calista, Crystal, Cherry, Clementine, Cosmo, Caspian, Cassian, Caspar, Colby
Dulcie, Devon, Delphi, Demelza, Diego, Darius, Denzil, Dustin
Everly, Ember, Echo, Eden, Elowen, Elora, Evadne, Ellis, Evan, Enzo
Fern, Flavia, Fallon, Faye, Flynn, Fitch, Ferdi
Giselle, Genesis, Guinevere, Gabriel, Gaius
Hazel, Honey, Harmony, Harper, Heather, Halo, Hendrix
Iona, Inez, Imelda, Isolde, Inigo, Ivan
Juniper, Jonquil, Jasmine, June, July, Juno, Journey, Jesse, Jude, Javen, Jago
Kiki, Keziah, Keltie, Kenya, Kit
Liara, Leonie, Lorelai, Liandra, Lena, Lyla, Lyra, Lyric, Lennox, Logan, Lorcan
Misty, Meadow, Mabel, Mala, Mila, Mika, Milo
I'm seriously too tired to finish the alphabet!
Raine, River, Rainbow, Raven, Phoenix, Rowan, Robin, Sage, Sorrel, Saffron, Reed, Rio, Tate, Tanner, Quinn