This Art Smock has got your kids covered. Put it on the front and velcro in the back at the neck to cover your artist down to the wrists. Can be made with PUL, Oilcloth, or cotton. 1-1.5 yards needed for each art smock.
$20 when you provide the fabric (custom)
$40 when you buy pre-made
S: 2-3T
M: 4-6T
L: 7-9T