I don't think this is the case like Gatsby was. Because there's also lots of Danny Elfman's music... Well but I'm not 100% sure, you can be right, too. I guess everything's possible (it's Lana + Burton after all).
I think her voice is sort of similiar to Lana's when she sings deep notes
For example in MØ's song collaborated with Avicii, lots of people thought that it's Lana singing it. (Sorry don't know how to add video)
https://www.youtube.com/watch?list=UU8xmjTfSP4reB6ZS7K-OGMg&v=MfeZG6K1JRw&feature=player_detailpage#t=61