Agree with others that Cassia is a great fit.
Other ideas - Gia, Iris and ...
Aven, Alexis, April, Aurora, Alba, Aphra, Amaya, Astrid, Bronte, Bethan, Bryony, Belle, Celyn, Celest, Connie, Claire, Carmen, Corinne, Cleo, Delphi, Dulcie, Danica, Diana, Etta, Evadne, Erin, Erica, Eden, Fenella, Faith, Fleur, Hazel, Hope, Harmony, Honor, Juliet, Jessamy, Josie, Juno, Juniper, Jemima, Jacinta, Keziah, Katy, Keira, Lyra, Lara, Liara, Luana, Lena, Larissa, Lorelai, Lois, Miranda, Marta, Mabel, Marnie, Mala, Mika, Mila, Noa, Niamh, Noelle, Nina, Nadia, Naomi, Opal, Ondine, Odette, Olive, Pearl, Pippa, Polly, Piper, Quinn, Romy, Remy, Robyn, Rowan, Rowena, Rose, Rita, Reagan, Saffron, Sadie, Sorrel, Sylvie, Stella, Skye, Samara, Saskia, Serena,Tamara, Tanya, Taryn, Tegan, Verity, Vashti, Wren, Willa, Xanthe, Zeryn, Zelda, Zillah, Zara