Flora - it's ok. Would probably use Florence and shorten.
Cora - it's ok. Much prefer Cara
Annabel, nickname Bel - really like Annabel but not Bel.
Mila - love it
Marla - love it but have only come across it spelled Mala which I like even better (poss only because it's the name of one of my best friends though!)
Alana - really like it
Carey - never come across. I don't think I'm keen.
Other ideas:
Arwen, Aphra, Alba, Aria, Ayla, Aya, Avril, April, Ariel, Amber, Autumn, Bronte, Brodie, Briar, Carys, Cerys, Cleo, Coco, Casey, Dana, Darcey, Dulcie, Eden, Erin, Effie, Enya, Edie, Esme, Elodie, Fallon, Ffion, Giselle, Gracie, Hana, Hallie, Hayley, Harley, Hadley, Iris, Iona, India, Jocelyn, Josie, Kayla, Kyra, Kyah, Kiki, Livia, Lilia, Lana, Lyla, Leona, Mika, Nia, Nyah, Nina, Nadia, Piper, Polly, Quinn, Rosa, Ruby, Ria, Sadie, Sorrel, Saffron, Saskia, Thea, Tara, Tansy, Verity, Willow, Zia