I'm not an expert in KOF style but so far I know, the light for the shading has to directly target to the character from diagonally above. (Don't light him/her behind) It's different from CVS style which only lights characters from straight above. For colors, if you want to use the colors from KOF, you need to have all KOF sprited characters for reference including those from NGBC and KOF 94-03 and KOFXI. Also, you need to look at them as reference for spriting. Here's a trick. If you want to create a KOF style, think about making characters look realistic, maybe like real life I think.