This is such a great idea! Vivi was my favorite character in FF9, so it's cool to see Roxas dressed like him, and I like that Namine matches! Lol, Rox's symbolic flame-heart.... XD
The black mage design is based of the old school design from like the first Final Fantasies, including the white mage one :3. FF9 does take a lot from the original either way, it's why it's my favorite 
.
.