Part of me likes the "Liar" part of Liara, it's dark and eerie. If you want a dark and eerie pick, go for Liara.
Lara is prettily classy if you prefer that sort of thing. I suppose some might find Liara a little flimsy and I do see how it could be perceived that way. I would bulk it up with a formidable middle name in that case.
Or maybe I'd think of it like this: Do I like
Lia, Ella/Ellie, or
Lara better? Because I bet an
Elara or Liara would be shortened, but it's pretty hard to shorten
Lara. In that case I'd pick
Lara, personally.
Just to be difficult, might I interest you in Elaia, the ancient Greek word for the olive tree? I think it's beautiful and your choices reminded me of it.