Third Girl

[FearlessFairy]

Isabelle, Francesca and.....

Alessia
Charlotte
Alexandra
Sophie/Sophia
Harriet
Felicity

Emmeline
Violet
Larissa
Matilda

Eleanor
Martha
Claudia
Cecily
Helena
Juliet
Sienna
Genevieve
Marianne
Imogen

Charlotte, Chloe

Was going to say Felicty too. Somehow it's really works.

Also like Izzy, Fran and Flick.

Isabelle francesca and juliette
Helena
Marianne
Louisa

Zara

Marianne
Genevieve
Juliet
Lucienne
Cassia
Serena
Claudia
Adela
Cecily
Verity
Rosemary
Caroline
Leonora

And Rosaria...

Doris

Beatrix
Cordelia
Tabitha
Penelope
Margot
Caroline

Angela

Annora
Leanora
Bethia
Calanthe
Evelina
Lucinda
Silvia
Also thought of Alexandra, Felicity, and Eleanor

Josephine
Rosanna
Alicia
Elizabeth
Dolores
Octavia
Juliana
Loretta

Juliet

Sophie/Sophia
Juliet
Cecilia
Louisa
Anna
Charlotte
Harriet
Lucy
Jemima

Adelaide
Rebecca
Julia

I was going to suggest Georgia but love Alexandra as suggested by others.

Gabrielle or Gabriella go nicely.

Aurelia

Isabelle Francesca and
Victoria
Eleanor
Scarlett
Alexandra
Amelia.
Charlotte
Louisa

You have a French sounding name and an Italian sounding one (both 3 syllables and both popular) for her sisters , so I'd choose another 3 syllable popular "European" name (not ending in A or L or starting with I or F) to "fit" nicely. Maybe Emily, Evelyn or Harriet?

Imogen
Christina
Elisabeth
Bethany
Marianne
Susannah

@IamnotwhouthinkIam makes sense. I like the suggestion of Harriet. Maybe Mallory, Romily, Beatrice, Beatrix or Verity work too.

Alice
Georgia
Violet