I don't plan on doing anyone from S-Cry-Ed, but I do have a suggestion for anyone going as Kazuma.
Get tight fitting underarmor, Black or Red if you can get it. It is the best material I can think of that would work for his sleeves. Other than that, I don't see any other major hurdles to jump for a Kazuma costume.
I doubt a simple HOLY costume wouldn't be that hard either. I believe most of them are two colors, and could be pretty easy to sew.