Lucas is perfect with Isaac and Oscar.
I don't like Sybil or Nancy. Alice and Annie are nice, though I would only use Annie as a nickname for an 'An...' name - Annabel, Angelica, Anastasia, Anna, Anika etc
Other girl names on the same lines:
Betsy, Bronte, Bonnie, Clara, Connie, Celest, Daphne, Dora, Elsie, Edith, Esme, Greta, Honor, Ida, Ivy, Iris, Judy, June, July, Juliet, Lydia, Mary, Martha, Maisy, Nora, Nina, Olive, Orla, Posy, Ruby, Rosa, Sadie, Stella, Sorrel, Tessa, Tara, Veda