How sturdy, and how authentic-looking? You could make the torso out of cardboard boxes and the arm portions might be made from wrapping paper cardboard tubes. You could buy red duck tape to cover the cardboard--it wouldn't give the exact same look, but people make amazing things out of duck tape so you might be able to make it work out. A tube made out of posterboard could be used for a base for a lightweight hat.
(Sitting in that costume might be a challenge!)
I don't know the size of the wearer's feet, but the footwear looks suspiciously like Kleenex boxes...
That looks like its a wooden shell. The pants look like tights, and the boots are wooden too.. i dont imagine these costumes being very home-made friendly..
That's the beauty of them. They look wooden but aren't. Every flexible joint that a person has must remain flexible in the costume or the person couldn't move. Those boots are in two pieces, the boxy shoe and the shin cover with black socks underneath to hide the join at the ankle. The chest piece could be carefully replicated with cardboard, but is more than likely a fiberglass or plastic shell. The arms could be replicated with PVC, with an upside-down U shape cut out at the inner elbow of the two pieces to allow for movement.