I think you are getting the U.S. vote and I would like to see those from the U.K. and its Commonwealth countries opt in on this one.
As you know I love [name]Cara[/name] and I know that you decided on [name]Eve[/name]. So, I will start thinking about it again.
If we look at the time when [name]Sidney[/name] was popular you would have found lots of Evelyns too, there would have been no Caras but of course there would have been Carolines but it doesn’t appeal to you, then there would have been Charlottes too and if we liked that and stretched the boundaries we could have a nn of [name]Cara[/name] but not sure about the Sh of [name]Charlotte[/name] and S of [name]Sidney[/name] together a bit of a tongue twister?
So, at the moment imo the obvious siblings of the day for [name]Sidney[/name] would have been the following:
[name]Evelyn[/name] and [name]Charlotte[/name] and sisters [name]Violet[/name], [name]Dorothy[/name], [name]Margaret[/name] or [name]Elizabeth[/name].
I think these vintage style names work with [name]Sidney[/name], however, you are bringing a more modern vibe to the table with [name]Eve[/name] and [name]Cara[/name]. I love the combo of [name]Cara[/name] [name]Matthews[/name] more than [name]Eve[/name] [name]Matthews[/name] even though both are lovely. I am positive that if you got more U.K. input that there would be a swing towards [name]Cara[/name].
[name]Cara[/name]'s sisters could be [name]Megan[/name], [name]Julia[/name], [name]Frances[/name], [name]Serena[/name], [name]Audrey[/name], [name]Isla[/name], [name]Imogen[/name], [name]Ellen[/name] and [name]Lucy[/name]
[name]Eve[/name]'s sisters could be [name]Sophia[/name]/e, [name]NIna[/name], [name]Abigail[/name], [name]Amelia[/name], [name]Leila[/name], [name]Iris[/name], [name]Delia[/name], [name]Nerida[/name] and [name]Lucy[/name]
In fact after looking at the names I think that most of the alternatives I suggested work with either name.
If it is of any help, and it probably isn’t would [name]Clara[/name] be an option? I love [name]Cara[/name] more but throwing it into the mix.
[name]Eve[/name] is a very pretty name, I am not so fond of the nn of [name]Evie[/name] which gets a lot of love here. I am pretty sure that you will go with [name]Eve[/name], and [name]Eve[/name] [name]Lucinda[/name] is lovely.
(I thought about [name]Lucinda[/name] and [name]Sidney[/name] in fn spot and the ‘s’ sound was too obvious in the first name spot.) ps I have had second thoughts on this and I like [name]Lucinda[/name] [name]Evelyn[/name] nn of [name]Lucy[/name], [name]Sid[/name] and [name]Lucy[/name].
With [name]Sidney[/name] I prefer a longer first name with a modern vintage vibe like [name]Evelyn[/name]/[name]Abigail[/name] (not too frilly) and [name]Amelia[/name]/[name]Viola[/name] (frilly) or as previously suggested [name]Lucinda[/name] [name]Evelyn[/name]
all the best,
rollo