Alba - really like it.
April - really like it
Cara - quite like it
Penny - not keen, especially as a nn for Penelope which I dislike
Stella - not keen
Violet - quite like it
I'd definitely go for Alba or April from your list, probably Alba.
Names with a similar feel:
Astrid, Aphra, Ariel, Aria, Ayla, Anya, Asia, Autumn, Aurora, Aliya, Bronte, Briar, Bryony, Clara, Cora, Coralie, Callie, Cassia, Cherish, Ciara, Carys, Cerys, Celest, Cecily, Camilla, Dulcie, Daphne, Della, Effie, Etta, Enya, Esther, Eden, Erin, Erica, Elsa, Edie, Esme, Farrah, Fallon, Faith, Greta, Giselle, Hanna, Honor, Hope, Hester, Iris, Ida, Ivy, Inaya, India, Juliet, Kyah, Kate, Livia, Leona, Lorelai, Larissa, Libby, Lottie, Lindy, Lara, Lyra, Lila, Mila, Mala, Mara, Mirren, Marnie, Marcia, Marianne, Miranda, Melody, Nora, Nell, Nancy, Nyah, Nadia, Nina, Orla, Pippa, Poppy, Polly, Posy, Ruby, Rosa, Robina, Rowena, Romilly, Robyn, Rhiann, Sylvia, Sara, Sadie, Sienna, Sorrel, Saffron, Summer, Scarlet, Skye, Tamsin, Tamara, Tessa, Thea, Taryn, Verity, Vanessa, Willa