I love halloween costumes! Good on you for picking brown, those are the absolute easiest colors to come by in faux fur, and tend to be cheaper too! Hooves seem to be a bit harder to construct, not material wise but the look, so maybe clawed feet-paws are better? I think a knubby tail would be appropriate for the design you want, because you're likely going to use some very long fur for the body and a waggy tail is going to make him look less like a monster and more like an overgrown puppy dog. Green or Orange eyes for halloween always do it, but for those more adventurous there's purple, yellow, or even lighter blue to think of.

As for construction to get some good lookin' digitigrade legs I suggest Matrices' site: http://www.matrices.net/digitigrade.asp for some fully functioning legs that look awesome regardless. I cheat and use Crayola quick dry foam for the nose and the gums/tongue (if the mouth is going to be open) and Sculpey Clay in any color other than stark white for the teeth, which you then push into the quick dry foam (after you've cooked it), and it makes a perfect jawset. It also looks like you have some strange anatomy with this creature, to which I suggest making a foam hump on your back and making a wire neck extension so that you aren't looking out the eyes, but black spaces at the base of the horns. That way you can keep the posture of your creature without having to always hunch over.

Sorry for the long reply.

Thank you very much! I didn't know that brown was the easiest to find and sometimes cheaper... or about the teeth things. I was planning on adding a hump on the back and all. I think I might add arm extensions or something. I don't mind being hunched over actually.. As I am pretty much all day on the computer. xD I've gotten used to it. Lol.
Anything else is greatly appreciated!

You can follow a million and one tutorials online on how to make heads, but the easiest way is to buy some apolstery foam (seat cushion foam) and to cut it how you want to shape the head on top of either a plastic mesh or thin cardboard. Use hot glue for EVERYTHING *lol* Sewing on the head gives strange bumps, but before you fur the head do the eyes first. Cheapest see-thru material is Panty Hose, and depending on whether or not you make things visible through the tear ducts, the pupils, or from the entire area around where you place a smaller eye. Assuming you're not making a toony monster, pupils are out of the question. You can buy taxidermy eyes pretty cheap at places like Cabellas (sometimes) or you can try to find glass of plastic half spheres somewhere (I haven't) and paint the flat side. I suggest taxidermy or self made glass or plastic eyes because they will glow completely with a backlit L.E.D.

You're going to want breathing holes in good places throughout your mask, because while the inside of your frame will be hollow you'll be covered by insulating foam and fabric. Don't fry your brain, and make some small holes through the mouth and the bottom of the jaw, or buy a small fan and put it in the nose.

Extended hands are funny, make sure to reinforce them with something thin and durable like wire, and to pose the hands in either a grab or a fist. Mechanical hands are hard to make, but not impossible with the right length of string and elastic or springs.