I think it's pretty.
Sylvia seems really stiff and formal, and
Silva is her light-hearted twin.
Silvia is nice too. I like it for a girl.
From your list I like:
Silva AlexandraArabellaColetteDianaEvangelineIrisMagdalenMarjorieMarloweMaxineXanthe
ArinAdamAdrianAngelCristianHenriTiberiusTristan
Silver is interesting, but I personally see it as more of a pet name or middle
Good stuff!
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