I love the name Silvia! (but prefer the Sylvia spelling) I've considered adding it to my own list a few times. It doesn't seem old ladyish at all, and most likely the only reason your family thinks it does is because of your great aunt. Use it! You love it and you loved your aunt, negative opinions shouldn't trump these reasons.
For combos perhapes Silvia Christine, Silvia Ruth, Silvia Emmaline, Silvia Dawn, Silvia Fern, Silvia Celeste, Silvia Jane, Silvia Beth, Silvia Violet, Silvia Charlotte, Sivia Alice or Silvia Abigail. I also really like the pp suggustion of Silvia Claire.
It is NOT at all too old-ladyish, especially considering how popular vintage/revival names are right now. (I'm sure plenty of people were saying that Ava was old-ladyish a couple years ago.) Silvia is pretty and will fit right in with other little babies born around this time, without being SUPER trendy. Your family is just a bit behind the naming fashions. ;)
I much prefer the spelling Sylvia, as I feel like it's more standard and also looks better. But, if the person you are honoring spelled her name Silvia, that's a legit reason to spell it that way.
I grew up with one Sylvia who is late 20s now. She always wore it well, from the time I met her at 10 til now. We did joke that we both had old lady names (I am Lois), but neither of us disliked our names. And now it will be even more normal to be a Sylvia now than it was 10-15 years ago, because, as I said, these classic names are more and more common these days.
GO FOR IT! Is my vote. Also, Silvia Clare is lovely. (I like this spelling of Claremore than Claire since Silvia to reduce the i overload.)
Nope! Not too old at all.
Definitely not an old lady name! I think it's beautiful, classy and sweet.
I think its cute, especially Sylvie as a nickname. I think its spunky.