Anyone notice something behind ansem and xemnas well i know behind xemnas is ansems hair and behind ansem is xemnas hair and in bbs final mix why r the unversed purple.

It's a common thing they do in the Final Mixes. They often change the enemies' colour palet.

1. Ansem SoD and Xemnas are behind each other if you look closely at the edges.

 

2. Like Baylaust said, it's common for Final Mix's to change the color of the enemies.

they get recolored