the shirt. No clue. I changed my mind from Twilight Town to ORG 13 when money became an issue. I'd suggest a black wife beater for the black and make a short sleeved button up shirt for the white jacket, sewing on a checkered ribbon or something for the pattern. Makign it gives you the chance to do the piping you'll need for the weirdness in the fabric... maybe base it off a hoody to get those two little pockets in the front?
I used the Eva wig from a tutorial on this site for Roxas, it should be in the wig section, something about 'emo hair'. Here: http://forums.cosplay.com/showthread.php?t=97834
The styling is time consuming, even with a blow dryer. Since I'm an amateur at wig styling, mine came out only slightly resembling it, with much less spikes. I used Got 2b Glued air blast and gel to get the spikes and blow dried them into place with pins and stuff. Any wig like Roxas with all those spikes will require heavy styling, think of it as a challenge :3
No pics, yet, still working on it!