Lux's Japanese voice is hands down Axel from Kingdom Hearts 2. He also does the voice for Reno in Advent Children FF7 but I couldn't find a Japanese Clip Red haired hotty for the blue kitty!
Lastly, a blue kitty should be voice by a blue kitty so Suwabe Junichi, who is also the voice of Grimmjow from Bleach, is Lux's Japanese counterpart for singing. Just have a listen! He fits very well for Lux.