I'm with Theodora'sMommy and
Raven Briar on
Tiara. To me it sounds like the namer expected the girl to become a beauty pageant contestant. It has a pretty-princess vibe, sort of like a less extreme version of naming a girl Sparkle. I don't think I'd have quite the same reaction to Crown (though that doesn't sound particularly name-y). A tiara, in my mind, is more diminutive and frivolous than a crown.
Tiana is okay but sounds insubstantial to me. For what it's worth, though, I also think
Lisa,
Amy,
Ella and
Mia sound insubstantial, so it might just be me.