I try to answer this (sorry for my english).
1) Yes, his real name is Enrique. He was born in Colombia and when he was 3 years old he went to Japan. You can read more about him in
Wikipedia or in his
Official Website
2)Well, I think it's a "Discography Thing". When she signed under Avex label she "started" her carrer. There is an example that can answer this question: Christina Aguilera's album JUST BE FREE (It's only an example, sorry about this). I think Ayumi don't think about Nothing from Nothing like her real debut because don't reflect her musical talent and all her feeling (A Song for XX is a personal album).
<3 Hope this help you ^__^