I'll just throw my appreciation on the pile here. Fan-bloody-tastic work! I can't wait to see the final result. Are you planning on sculpting in Mudbox as well as texturing @Ulrick?
one thing I'm seeing right off the bat is that there's no triangles. If you're preparing this for a game ready situation don't be afraid to use triangles. For sculpting they can cause headaches but at this stage they are your friend.
Hey DoubleLeaf! These sculpts are gorgeous. I'm constantly impressed with how amazing these shots look. Rendering is something I'd love to get better at, so any words on this "blue mat" render process?
The sculpt is awesome, but your textures are really lacking. The skin texture in the concept is pretty plain but I think you could do more with it without straying from the concept. Same goes for the clothes.
72 hours? Thats... A huge number of hours for such a small prop? Wires and texture flats would help, as this looks atm like a crazy bump filtered item and not a sculpted/sub-d mesh.
Since you've already got the details sculpted out, this is your best option. You could also look into using Decimation Master, but chances are the resulting mesh would be too messy to UV.
The bunching of the leathery fabric is looking a bit strange in a few places, particularly on the knees. I think it'd be worth hunting down some good references of similar costumes and revisiting your sculpt there.
What onionhead said about creaing is prolly the best way to go. another similar aproach would be using the sculpt geo tool to pinch the sharp edges if your mesh is dense enough
Are you using the zBrush 4? You could just use a clipping brush. That would get rid of the end of the tongue right away, then you could just sculpt in the surface damage/noise.