I might be able to help you out with the mask situation. I went as Hollow Ichigo in his Horn-mask form. [points to forum icon] and the mask shouldn't take more than 2 weeks of work if you paper mache correctly. AND you'll be left with a very sturdy mask.
For starters, we used this mask
as a base for the mache. Obviously any mask will do, we just used this to get the closest to the mask's base as we could. So you slap on 4 layers of mache around down to right before the teeth. Then mache the back side of the mask from the jaw down, 4 layers again, and then super glue the two.
For the dome like effect, we just re-mached the forehead piece 4 times, and connected them until we were satisfied, cutting up and using left overs to make the jagged edges of the back end. For the raised eyebrows, strip a couple Q-tips, and glue them at the brow, and then paper mache over. To cover the eyes, get a very light fabric and cover it and the jaw bone gaps. It should allow you to still see, but nothing to be seen on the inside.
The horns were probably the hardest part. For us, we basically printed out rectangles and molded them into place [note; the horns didn't hold for more than 2 days at Otakon before they ripped] My own personal idea for the horns is just taking wire, bending it into place, and macheing it about 3 or 4 times. Once all said and done with the mask assembly, spray paint it with a layer of non-matte White to give it a good solid look.
Last little details. For the markings, either tape down the mask and spray paint them on, use a sharpie, or acrylic paint them. As for the teeth, you can use Fake French-cut Fingernails [they sell them in 100 packs at target for under 10 bucks]. Just remember to paint them white before hand. and that should about do it.