Clones?!

[Squall of SeeD]

because Tidus Is a dream of the Fayth and the Fayth used Shuyin for Tidus

They couldn't have. Refer to the Posts above yours. The matter is not nearly so cut and dry.

[SeeDRankLou]

They don't. Without the Songstress Dressphere, they look nothing alike aside from both being brunettes. For that matter, Lenne's hair is darker and longer, so even that isn't all that similar. The most their appearances have in common is that they are both girls.

The contrast between long hair and short hair can make a person look miraculously different. I think they look just as similar as Tidus and Shuyin look, it's just that Lenne's long hair is making her face look that much more different.

Tidus and Shuyin look similar for dramatic effect, just as Yuna and Lenne do. It's symbolism. Ironically, it's Yuna and Shuyin who share the situational similarities, as well as Tidus and Lenne. They are all connected, which is one of the themes of the game. It's very similar to the situational dramatic effect in Final Fantasy VIII. Laguna and Julia couldn't be in love because they couldn't overcome the events in their lives. But Laguna's child and Julia's child have been given that same opportunity, and despite the events in their lives, they were able to overcome them and be together.

[Aurion]

Wait, a freind told me that he had to fight Shuyin and Vegnagun at the end. Is that because Shuyin was still trying 2 destroy Spria a 2nd time? If so, didn't Squall of SeeD say that both the original and aeon Shuyin were dead. So, how did Shuyin come back? Was he a ghost or something? Was he like Seymore( FFX) who seemed to never die?
If so, did Shuyin come back from the Farplane, or was he never really dead? Maybe he was waiting for the right time 2 strike!....I might be onto a FF conspiracy theory...Yay me!

[Squall of SeeD]

Wait, a freind told me that he had to fight Shuyin and Vegnagun at the end. Is that because Shuyin was still trying 2 destroy Spria a 2nd time? If so, didn't Squall of SeeD say that both the original and aeon Shuyin were dead. So, how did Shuyin come back? Was he a ghost or something? Was he like Seymore( FFX) who seemed to never die?
If so, did Shuyin come back from the Farplane, or was he never really dead? Maybe he was waiting for the right time 2 strike!....I might be onto a FF conspiracy theory...Yay me!

He's fought at the end because he was being hostile. Yuna tried to reach out to him and make him think she was Lenne and calm his hatred and anger by carrying Lenne's words of "I love you" to him. However, he saw that she wasn't Lenne at that point and tried to kill her.

And, yes, Shuyin was -- like Seymour --an Unsent.