I really like your girl list. Overall I'd say it gives a 'well used but not super popular and more contemporary than classic/timeless' vibe. In that vein, I would suggest:
Amaya, Anya, Alyssa, Alexis, Ariel, April, Aria, Bronte, Billie, Carys, Cerys, Celest, Cherry, Cassidy, Delphi, Darcey, Everley, Erin, Evana, Etta, Effie, Fallon, Fenella, Giselle, Greta, Halle, Heidi, Harper, India, Iona, Josie, Jessamy, Kiki, Keira, Lois, Lyra, Luana, Liara, Mila, Mika, Mala, Nova, Nyah, Nadia, Ondine, Odette, Piper, Pippa, Quinn, Remy, Romy, Romilly, Ramona, Robyn, Saffron, Sorrel, Saskia, Serena, Skye, Thea, Tamsin, Taryn, Verity, Wynter, Xanthe, Zara, Zinnia
But I think Elijah 'goes' better with another Christian/Jewish name like:
Abigail, Anna, Ada, Blessing, Delilah, Deborah, Eden (already on your list, I know - good match imo), Elizabeth, Esther, Eve, Faith, Felicity, Grace, Genesis, Hannah, Hope, Joanna, Jemima, Keziah, Lydia, Leah, Miracle, Mary, Martha, Margaret, Miriam, Naomi, Noa, Neriah, Patience, Phoebe, Rebekah, Rachel, Ruth, Sarah, Serah, Tamar/a, Trinity, Tabitha, Zipporah
I don't really think sibling names have to 'go' though.