Before the game was released, many fans were curious about the connection between Lenne and Yuna. This raised many questions, the most being if they were clones, or related in blood.
The truth is, they're not clones.Even the difference between their existance is about a thousand years. However, they were both summoners at one point. Shuyin even mistakes Yuna for Lenne, because of the Songstress dressphere she had on at the time. Unlike Tidus and Shuyin, any similarities they seem to share are a mere coincidence.
The most notable diffences they share are in hair and eyes. Yuna has Heterochromia irids; one eye is blue, the other green. Lenne's eyes are brown, and of slightly larger shape. Yuna's hair is short, and Lenne's is long. Their eyebrows take a different shape as well. In some artwork by Nomura, Lenne's complection is significantly darker than Yuna's. However, in FMVs they're not exactly evident of that.