I see some problems. Firstly, the package will eventually grow too big. Secondly, a lot more people want outfits, lots of people didn't get the chance to enter the contest. Thirdly, the likelyness of seeing your new outfit is slim.

I am a modder and artist, and these kinds of things are not easy to achieve. You would need exact grids and correct shading to match the style. Also people would want hair, face paint, skin tones, etc.

You probably should wait until the game has been out for a few weeks, then work in getting a team together (artist, modder, colourer, shader, etc)
But even then this will take time. I'll send you a message with what I suggest you do to organize this.