On the note of Yonin/Innin placement. It would be nice to make a JA, trait, or spell to ignore placement for a short time. For example if the Enemy changes position and or moves around. You can use Tsukiyomi(just using a name that uses dark/light attributes) to regain or control the enmity that is running around. Or use Ninjutsu and any location within a certain time limit(if it was a trait it would say "occ. ignores position").

On another note, an offensive Dark and light ninjutsu would be nice, even if it doesn't fit the Elemental wheel, the -30 dark resistance would be good for Kurayami.