I don't think that's allowed KAT. The consensus here is that we feel artists should try work from the ground up, despite there SUPPOSED poor ability. It's ok to reference from professional, or other sprites(though I'd never consider mk professional...blegh), it's just that when a person does this for a certain amount of time, they develop bad styling habits that turn out very hard to drop in their later years. I don't think you'll be disqualified, but instead, I just think that your current piece won't be accepted into the competition.
good luck with your other future ninja piece!