My son's 5th birthday party was last Saturday, and we did a Minecraft cake. It was actually square cupcakes (chocolate with green grass and white cake with white frosting for Sandstone, and blue jello), which worked great for serving, but was a pain for making (I did it all from scratch). We had a luau with a lot of water activities in the backyard, and the only thing Minecraft was the cake (and some of his presents from his friends). Of the 6 families there (about 15 kids total), about half of the kids were into Minecraft, the others hadn't heard of it. The ones that didn't know didn't care one way or the other. I would omit the papercraft if I were you, they won't do it there if they are wet and having fun at the party, and they probably won't do it at home either.