The major domains of development are physical, cognitive, language, and social-emotional. Children often experience a significant and obvious change in one domain at a time.
No. Don't use rub on wax. It's a waste of money and you'll be lucky if the wax lasts more than a few runs. Rub on wax is designed as a temporary solution and it comes off after 2-3 runs leaving you just as slow as before you rubbed on the wax.
He had a larger body-double who wore his prosthetics (beard etc.) in some shots. They also used optical illusions. There were two sets for Hagrid's Hut,a small one which Hagrid went in to look big and a large one which the trio went in to make him look even bigger.