[name_f]Acacia[/name_f]
[name_f]Ariella[/name_f]
[name_f]Cassia[/name_f]
[name_u]Cassidy[/name_u]
[name_f]Clara[/name_f]
[name_f]Galilee[/name_f]
[name_u]Indiana[/name_u]
[name_f]Kallia[/name_f]
[name_f]Keira[/name_f]
Liara/[name_f]Liana[/name_f]
[name_f]Lucia[/name_f]
[name_f]Maelie[/name_f]
Middle name will probably be [name_f]Olive[/name_f] or [name_f]Katie[/name_f]
I love [name_f]Maelie[/name_f]. It goes perfectly with [name_f]Sienna[/name_f]! However, I do think that neither [name_f]Olive[/name_f] or [name_f]Katie[/name_f] go very well with [name_f]Maelie[/name_f] because of the similar sounds. [name_m]How[/name_m] about [name_f]Maelie[/name_f] [name_f]Juliet[/name_f] or [name_f]Maelie[/name_f] [name_f]Vivienne[/name_f]? [name_f]Sienna[/name_f] and [name_u]Cassidy[/name_u] also go really well together! Good luck!
[name_f]Sienna[/name_f] & [name_f]Ariella[/name_f] [name_f]Olive[/name_f]!! What an adorable sibset. You have many beautiful choices tho, so whatever you go with will be lovely!
All the best.
[name_f]Cassia[/name_f], [name_u]Indiana[/name_u], [name_f]Keira[/name_f], or [name_f]Lucia[/name_f] seem to go best. I think my favorite would be [name_f]Cassia[/name_f] with [name_f]Sienna[/name_f].
[name_f]Sienna[/name_f] is lovely and reads quite feminine so I would choose one of a similar vibe. [name_u]Cassidy[/name_u] and [name_f]Indianna[/name_f] are unisex to me so they are my least favourite for you. [name_f]Sienna[/name_f] with [name_f]Ariella[/name_f], [name_f]Maelie[/name_f], [name_f]Cassia[/name_f], or [name_f]Lucia[/name_f] are beautiful together!
You have some good names on your list. Personally I like Cassia, Clara, Keira, Liana and Lucia. For a sister Sienna I think the best fit is Cassia.
I prefer Katie to Olive.
Best of luck.
To my ear, the best fits are [name_f]Cassia[/name_f], [name_f]Lucia[/name_f], [name_f]Ariella[/name_f], and [name_f]Keira[/name_f]. I think [name_f]Olive[/name_f] works best in the middle except with [name_f]Ariella[/name_f], where I prefer [name_f]Katie[/name_f].
[name_f]Cassia[/name_f] or [name_f]Lucia[/name_f] 
[name_f]Cassia[/name_f] and [name_f]Lucia[/name_f] are my favorites!
I like [name_f]Sienna[/name_f] and [name_f]Keira[/name_f].
Thank you so much for the feedback and suggestions!! [name_m]Will[/name_m] be talking to hubby! I think it’s probably out of [name_f]Lucia[/name_f] [name_f]Olive[/name_f] or [name_f]Lucia[/name_f] [name_f]Katie[/name_f] or [name_f]Cassia[/name_f] [name_f]Olive[/name_f] or [name_f]Cassia[/name_f] [name_f]Katie[/name_f].
[name_f]Do[/name_f] you think [name_f]Cassia[/name_f] [name_f]Katie[/name_f] is too much of the repeated “c” sound?
[name_u]Cassidy[/name_u] or [name_f]Maelie[/name_f]
I think [name_f]Sienna[/name_f] and [name_f]Lucia[/name_f] are gorgeous together!
[name_f]Sienna[/name_f] is my #1, and [name_f]Clara[/name_f] is my #3! ([name_u]Everly[/name_u] is #2 for me!)
I think [name_f]Clara[/name_f] [name_f]Katie[/name_f] is so lovely.
I also like [name_u]Cassidy[/name_u] [name_f]Olive[/name_f], Liara [name_f]Katie[/name_f], [name_f]Maelie[/name_f] [name_f]Olive[/name_f] and perhaps [name_f]Lucia[/name_f] [name_f]Katie[/name_f].