Keith's eye color
in paint.net using dropper on his eye from the close-up face shot on here gives an RGB value of 70,70,98 for the lighter part and an RGB value of 23,23,39 for the darker part. the hue of this color is 240, which is solidly blue. hence, i conclude that his eye color is blue-grey. please keep it this way.
here is how the ninjapic looks with keith having purple eyes: