There are billions of references to other FFs in X-2.
The Atma joke was especially clever, when you think about how rabid some fans get about that "mistransation"; the FFVII hints were imaginative, too. Also, when Paine's in Dark Knight mode, she spins her sword above her head at the end of battle, a little like Cloud, except she uses two hands. Gun Mage Yuna's victory dance is the same as Laguna's from FFVIII... the dresspheres are full of clever, often hidden references.