I like both names but prefer [name_f]Juliet[/name_f] in this instance because it adds new sounds to the set and feels like a better style match. [name_f]Cecily[/name_f] also feels a little light weight compared to your daughters’ names.
[name_f][/name_f]I agree with the other comments regarding style. I would add Romantic.
[name_f][/name_f]If I was naming a sibling I’d consider:
[name_f][/name_f][name_f]Delia[/name_f]
[name_f][/name_f][name_f]Sonia[/name_f]
[name_f][/name_f][name_f]Diana[/name_f]
[name_f][/name_f][name_f]Moira[/name_f]
[name_f][/name_f][name_f]Carina[/name_f]
[name_f][/name_f][name_f]Cecilia[/name_f]
[name_f][/name_f][name_f]Sabine[/name_f]
[name_f][/name_f][name_f]Magda[/name_f]
[name_f][/name_f][name_f]Martha[/name_f]
[name_f][/name_f][name_f]Celeste[/name_f]
[name_f][/name_f][name_f]Isadora[/name_f]
[name_f][/name_f][name_f]Simone[/name_f]
[name_f][/name_f][name_f]Corinne[/name_f]
[name_f][/name_f][name_f]Florence[/name_f]
[name_f][/name_f][name_f]Georgina[/name_f]
[name_f][/name_f][name_f]Marianne[/name_f]
[name_f][/name_f][name_f]Anneliese[/name_f]
[name_m]Colin[/name_m]
[name_f][/name_f][name_m]Cyrus[/name_m]
[name_f][/name_f][name_m]Anton[/name_m]
[name_f][/name_f][name_m]Albert[/name_m]
[name_f][/name_f][name_m]Cedric[/name_m]
[name_f][/name_f][name_m]Simon[/name_m]
[name_f][/name_f][name_m]Abram[/name_m]
[name_f][/name_f][name_m]Walter[/name_m]
[name_f][/name_f][name_m]Harvey[/name_m]
[name_f][/name_f][name_m]Roland[/name_m]
[name_f][/name_f][name_m]Conrad[/name_m]
[name_f][/name_f][name_m]Vincent[/name_m]
[name_f][/name_f][name_m]Simeon[/name_m]
[name_f][/name_f][name_m]Douglas[/name_m]
[name_f][/name_f][name_m]Frederick[/name_m]
[name_f][/name_f][name_m]Solomon[/name_m]
[name_f][/name_f][name_m]Desmond[/name_m]