Clones?!

[Squall of SeeD]

now, because the real zanarkand was distroyed by bevelle,the fayth made the dream zanarkand and created all the people from the real zanarkand that were killed, but made them different, so shuyin is the base of tidus in the dream.

The Fayth really didn't have any control over anything. Yu Yevon did all the shaping, manifesting the memories of the Fayth into reality. However, Tidus is not based on Shuyin. Tidus lives in the present day of Aeon Zanarkand, 1000 years after it was created. Aeon Shuyin should long since be dead.

but im not sure y lenne and yuna look the same...

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.

i don't remember anyone asking about the dressphere at the start with leblanc in it but another thing how come tidus has no recollection of the machina war?

Because 1) he isn't Shuyin, 2) he lives 1000 years after both the original Shuyin and any Aeon Shuyin that lived would be dead, and 3) Aeon Zanarkand was never involved in the Machina War.