Girls:
Willa - ambivalent. Given how much more popular Willow is now, I think this might get head as Willow said with a lazy accent.
Sophia - very pretty. Super popular but that's because it's a lovely name.
Phoebe - really like it.
Boys:
Jesse - love, love, love it. My favourite boys' name.
Otis - not keen. My brain adds 'the aardvark' to it and I can't even remember why!
Seth - not keen. Quite a harsh sound somehow.
I'd go for Phoebe and Jesse.
Other ideas:
Anika, Astrid, April, Bronte, Bonnie, Bryony, Cassia, Clarissa, Cora, Daphne, Dana, Delilah, Erin, Erica, Evelyn, Flora, Frances, Felicity, Georgia, Grace, Greta, Hannah, Heidi, Harriet, Isla, Imogen, Isobel, Juliet, Josie, Jemima, Kitty, Katrina, Kathryn, Lois, Leonie, Libby, Martha, Maisy, Miranda, Nancy, Nell, Naomi, Olive, Ottilie, Olivia, Poppy, Philippa, Penny, Ruby, Rosalie, Ramona, Sadie, Scarlett, Saffron, Thea, Tamara, Tilly, Verity, Violet, Victoria, Wren, Xanthe, Zara
Arlo, Ashton, Aston, Bryn, Bodhi, Benedict, Colby, Conor, Cyrus, Declan, Ellis, Ethan, Elliot, Flynn, Fitch, Fergus, Hal, Ivan, Jude, Jasper, Justin, Kieran, Kit, Logan, Lorcan, Milo, Micah, Nico, Oscar, Owen, Orson, Perry, Patrick, Quinn, Reuben, Solly, Sonny, Theo, Teo, Vinnie, Victor, Xavier, Zac