I made my Jason Todd mask out of liquid latex.
You basically get a plastic mask, liquid latex, paint the latex on for quite a few coats (15+ plus), let it dry for about a day, come back, SLOWLY AND GENTLY peel it off using copious amounts of baby powder, and cut it into shape.
Can't help much on the cape though :/
Jason Todd (The Red Hood)
Jason Todd (Jason Todd and the Outlaws)