Sophie Diane is perfect; do not change one thing about it.
Sharon is a wonderful name. I don't like
Rose as a mn because the "rose of sharon" image is too obvious. Plus, in "The Grapes of Wrath" the character
Rose of
Sharon's name was pronounced something like "Rosa-Sharn," and now I can't get that out of my head. How about
Sharon Eve,
Sharon Tess,
Sharon Kate?
I'm not crazy about siblings sharing the same first initial. But here they have a different sound so I suppose it's not that bad.