Well, that could work, but that mask doesn't have any fangs! What I suggest is building up a clay sculpture of only nose, cheekbones, and mouth with fangs on a lifecast of your actor. Lifecast tutorials for facial prosthetics such as these can be found online. Use the same mold for both your appliances and mask, once you mold both sides of the actor's head, you trim it for the appliances. For the mask, only trim some of the bottom so that the mask fits over the ears, like an over-the-head mask, then attach the hair and stuff, and remember, always use either PAX Paint or the better and less work option, Rubber Mask Grease Paint, it works on skin and latex. Either that, or buy a cowl and prosthetics from either fxwarehouse.info or toxicimage.com, glue them together, and paint them with RMG Paint and add hair. It probably won't be cheap, but it will be the best solution.

Oh, almost forgot, use Monster Makers Mask Latex, you don't need to cure it, just pour it into a plaster mold.

We had a prosthetic mask from thecostumer.com. We glued it to a platic mask with a strap and colored the face with foundation and power to match the beast's face. We then took hair from the wig and glues a little around to edges. I have the mask and wig to rent if you are interested! Good luck!