Here is a lovely fabric I found! It is similar to the original artwork, the best I could find thus far - but it is all up to the cosplayer :) If this would be too different, I will happily hunt down another option!
This next photo has some of the other materials in it ^^ The string and buttons for the sleeve. Zipper is not pictured because it wasn't in stock yet :)
The smaller buttons are for the closure of the top under where the zipper is. And there is that sneaky little yellow receipt tag on the far right!