fabrics, see below about skinny arms and legs.
Although he is not terribly difficult to make the skinny arms and legs are a little challenging to turn and stuff. I would highly recommend using lighter weight fabrics as I am not sure the heavier ones, like the canvas will turn. Also matching the lines for the belt, and collar, and getting all the arms and legs lined up, and on the correct side of the project probably makes this a project for someone with at least a little sewing experience. A nice wooden chopstick will help you stuff him; my Fairfield Poly-Fil came with a similar stuffing tool.