I think [name_f]Briony[/name_f] and [name_f]Verity[/name_f] are too close to [name_f]Romilly[/name_f] - it sounds too matchy. [name_f]Vienna[/name_f] is a great one! Other feminine/not too popular options that sound nice with [name_f]Romilly[/name_f]:
[name_f]Vera[/name_f]
[name_f]Vada[/name_f]
[name_f]Sonya[/name_f]
[name_f]Harriet[/name_f]
[name_f]Marisa[/name_f] ("[name_f]Mare[/name_f]-ee-sah" with a hard e sound)
[name_u]Merritt[/name_u]
[name_f]Tessa[/name_f]
[name_f]Bianca[/name_f]
My favorite of your choices is [name_f]Verity[/name_f], but [name_f]Briony[/name_f] and [name_f]Verity[/name_f] are both a bit rhymey with [name_f]Romilly[/name_f]. So I’d prob go with [name_f]Vienna[/name_f].
My immediate thought was [name_f]Romilly[/name_f] & [name_f]Viveca[/name_f] (or [name_f]Viveka[/name_f]) – you like a couple of V- names so you may like this one – and [name_f]Romilly[/name_f] and [name_f]Saskia[/name_f].
[name_f]Briony[/name_f] and [name_f]Verity[/name_f] are cool, but too matchy with [name_f]Romilly[/name_f].
[name_f]Vienna[/name_f] is your best bet.
Or, maybe one of these:
[name_f]Briar[/name_f]
[name_f]Ivy[/name_f]
[name_f]Sienna[/name_f]
[name_f]Ravenna[/name_f]
[name_f]Dahlia[/name_f]
[name_f]Vera[/name_f]
[name_f]Verena[/name_f]
[name_u]Vida[/name_u]
[name_f]Viva[/name_f]
[name_u]Vesper[/name_u]
[name_u]Vale[/name_u]
[name_m]Valor[/name_m] (I like this for a girl since it is similar to [name_f]Valerie[/name_f])
[name_u]Merritt[/name_u]
[name_f]Athena[/name_f]
[name_f]Romilly[/name_f] and [name_u]Juniper[/name_u]
[name_f]Romilly[/name_f] and [name_f]Tallulah[/name_f]
[name_f]Romilly[/name_f] and [name_f]Bryony[/name_f]
[name_f]Romilly[/name_f] and [name_f]Vivienne[/name_f]
[name_f]Romilly[/name_f] and [name_f]Scarlett[/name_f]
[name_f]Romilly[/name_f] and [name_f]Petra[/name_f]
[name_f]Romilly[/name_f] and [name_u]Josie[/name_u]
[name_f]Romilly[/name_f] and [name_f]Willa[/name_f]
[name_f]Romilly[/name_f] and [name_f]Athena[/name_f]
[name_f]Romilly[/name_f] and [name_f]Kerensa[/name_f]
I love [name_f]Vienna[/name_f] as a sis to [name_f]Romilly[/name_f]: Veevee and [name_f]Enna[/name_f] as nicknames
Others: [name_f]Violet/name_f [name_f]Eliza[/name_f]([name_f]Liza[/name_f],[name_f]Ellie[/name_f],[name_m]Eli[/name_m] (as in the boys name) [name_f]Susanna[/name_f]( [name_f]Zuzu[/name_f], [name_f]Sana[/name_f],[name_f]Lilly[/name_f] ([name_f]Susanna[/name_f] means [name_f]Lily[/name_f]), [name_f]Savannah[/name_f](Sevvy, Vannah) [name_f]Kerensa[/name_f]([name_f]Keren[/name_f], [name_m]Karey[/name_m], Ensa, [name_u]Ren[/name_u])