I think [name]Alexandria[/name] is probably the most usable.
[name]Lavinia[/name] is a bit “eccentric English old lady”. But saying that,if I met a young adult or little girl [name]Lavinia[/name] it would probably change my mind a bit. Like the little girl I met named [name]Agnes[/name].
It depends on how vintage you want to go really. Neither are awful or out of place in the current sub trend for unusual vintage but still pretty girls names.
You could probably squeeze the nickname [name]Nina[/name] out of [name]Lavinia[/name] if you have nickname concerns.
I agree that neither name comes across as being too much of a guilty pleasure. They may be a bit on the frilly side, but both are lovely choices. I prefer [name]Alexandria[/name] myself, and you could always use the unisex nickname [name]Alex[/name], which might fit in more with your friends’ and colleagues’ tastes. I think it’s most important that you and your partner love the name, though, so if you love romantic Victorian names, I say go for it and don’t worry so much about what other people think.
[name]Katherine[/name] [name]Alexandria[/name] is gorgeous, BTW.
I like both, but [name]Lavinia[/name] more. I don’t consider either of them non-usable, although they are both uncommonly heard.
Neither of those qualify as guilty pleasures in my opinion. They’re both very usable.
I love [name]Lavinia[/name]!
Oh gosh neither seem guilty pleasure to me but I’d pretty much use anything and have 
I like [name]Lavinia[/name] nn Livi or [name]Avie[/name]!