Yup, the kneecap (patella) thing is true! Also, babies do not have all of their carpal bones when they are bone and there are many gaps (fontanels) in their skull where bone has not yet grown and fused together.
The milk thing is also true; however, the thinned white paint is used for the shots where it's flowing and cascading all over the place, they likely use something else for the "moustache" shots. Also, I once saw a bit on TV on how they prepare frozen turkey's for TV commercials. They showed that they only "spot" cook one part with a hair-dryer (that's the part they show being cut into), and they paint the rest of the turkey with an orange/brownish looking wood stain to give the appearance that it just came out of the oven.....mmmm.....