I love your list! Also, congratulations on twins!
What came to mind when I first saw your list:
[name_f]Dorothy[/name_f] [name_f]Iris[/name_f]
[name_f]Violet[/name_f] [name_f]Matilda[/name_f]
[name_f]Amabel[/name_f] [name_f]Tallulah[/name_f]
[name_f]Penelope[/name_f] [name_f]Sybil[/name_f]
[name_f]Edith[/name_f] [name_f]Marianne[/name_f]
[name_f]Felicity[/name_f] [name_f]Joan[/name_f]
[name_f]Matilda[/name_f] [name_f]Arden[/name_f]
More suggestions:
[name_f]Emmeline[/name_f]
[name_f]Amelie[/name_f]
[name_f]Linnea[/name_f]
[name_f]Lilia[/name_f]
[name_m]Silas[/name_m]
[name_m]Simeon[/name_m]
[name_m]Roman[/name_m]
[name_m]Bram[/name_m]