I looked at a picture of Barf on the web, seen the movie but it has been awhile.. I think the best way to make the costume work is a blond wig, and ears on a headband in a similar color. Like Witchy said, you can buy fur at Michael's or Hobby Lobby, etc, and maybe glue onto cheap gloves. Don't forget the name patch on his suit. The make-up and you are good to go! I think it will be awesome!
It is said that if you hear someone's footsteps behind you on the Halloween night, you should not turn back because it may be a dead following you. And if you commit the mistake of looking back, it is likely that you might join the dead very soon.