Knox is horrible, it reminds me of the words 'knocks', 'ox' and 'knuckles', lol.
Knox Leon isn't a good combo IMO, I just hear 'Knock Sleon.' whatever a Sleon is, hehe.
Vivienne Marcheline is really nice, but
Knox and
Vivienne is so mis-matched, and
Vivienne doesn't 'fit' with the names of the siblings at all, it's so much classier!