The jacket I can;t help with as I not only don't have a dang 3DS, but I haven't seen enough DDD Sora's to know exact details, but I can tell you, you will want a cotton fabric. A heavier kind. Do NOT get the cheap stuff..It's cheap for a reason..lol I personally like Classic Bottom Weight for these things. So I know it's a short jacket that looks like a hoodie..You can get a fitted slightly fitted hoodie pattern at a local fabric store. Then you will want to measure how long you will need it and gut the pattern to that length and add the pockets accordingly.
Anyway, onto the wig..I use arda-wigs.com for my spiked wigs. If you buy the jaguar in spanish brown it will be perfect for sora.See here:
This is not the right color, but it's the wig I mentioned..There are way too many tutorials online for sora wigs so you should be able to find one pretty easy if you don;t know how to style one yet..Youtube and google are you're friend here..But read the whole thing before starting..You might get to the end and not like how theirs looks then what are you gonna do lol Hope this helps