Full body to outfit top: shirt mesh not going away

I recently followed the tutorial on how to create a top from a full body outfit. It looked great until I opened the game and the shirt I used as the orignal mesh was able to be seen as a shadow through the shirt! Not only that, if I added a skirt or anything high waisted, the collar would turn the color of the skirt. Maybe UV mapping issues with that? I really could use some help with the previous mesh showing though, thank you.

Edit: I'm using a dress and top from Realm of magic