My fave is Diana- classical, strong, elegant and underused (although I must admit I don't like the nn Di).
I also quite like Lucia but I do think many people will pronounce it differently when they first see it (I would guess you'll get Loo -chee -ah only about half the time until they are told).
I think Olivia and Mia are a bit dull compared to your other choices, as they are so popular/trendy now (which is a shame in lovely Olivia's case imo).
Other suggestions that are the same style as your other choices to me: Louisa, Helena, Lara, Susannah, Serena, Thalia, Julia, Marina, Mariana, Lydia, Gaia, Claudia, Cecilia, Celia, Antonia, Octavia, Ophelia, Aurelia.