Ayumi's back-up chicks...

[pyro2787]

I agree, can't have the backup singers more beautiful than ayu, otherwise, everyone would stare at the backup singers the whole time and make ayu the third wheel, the short and dull one...she'll be left behind in the dust, and no matter how loud or how well she sings, the spotlight will fall on the backup singers and leave Ayu alone and oh so lonely and a dark corner with no one there to console her, all cold and hungry and so depressed.........haha, kidding, I like to exaggerate!

Anyways, the backup singers are Ayu's friend, think of what kind of person Ayu would be portrayed as if she ditches her friends and have them replaced because they make her concert less appealing...