Quote Originally Posted by SuperMillionaire View Post
Here's the thing, though: in the first game, how could they put in Cid Highwind and not Tifa Lockhart? Why did they leave her out and put Cid in? Why did they wait until Kingdom Hearts II to add her, and why did she have to wear her Advent Children attire instead of wearing a brand new outfit?
Because they wanted Cid instead of Tifa. It's really as simple as that.

Also, KHII came out the same year as Advent Children, all the FFVII characters that appeared in the sequel had their AC outfits on. That's why.