For the sweater, I'd definitely buy a red turtleneck/sweatshirt of some kind. For adding the wording, I'd suggest looking in to either Iron-on Transfers, or the freezer paper stencil method. Those are probably your best bets for neat, clean lettering. :3

For the cane, you could either get an actual cane and paint it yourself, or just buy a lawn decoration. As /u/psychan already mentioned, Amazon also has plenty of devil horn headbands and fashion glasses that should meet your needs.

As for the wig, since you're doing a fem version, I think you could probably choose any style that appeals to you, but I'd vote for the side-swept bangs ;3 Oh! And the skirt - how about adding some over the knee socks and some cute ankle boots? Red OTKs and black boots, to go with the black and red skirt?

Cute idea! Please post pics once you have it all together! :3