i think you would find out pretty quickly as the little demon would be sprinting round the hospital. They must show powers early bcus they have already "ruled out" the possibility that Jack Jack has powers? (even though he does they're just weird.) i swear tho a superfast baby and a baby that can turn invisible sound like the hardest kids to bring up, e.g. "HONEY WHERE THE HECK HAS VIOLET DISAPPEARED TO NOW I SWEAR SHE WAS JUST IN THE COT WTTFFF"
Iiiiiiiii don't think so. She was ABSOLUTELY CERTAIN that jack jack was powerless when it turned out he was just a LATE BLOOMER. MEANING DASH AND VIOLET WERE BORN WITH POWERS. FEEL SOOOOO SORRY FOR THEM
It is his nickname. His real name is Dashiell.
http://pixar.wikia.com/wiki/Dash_Parr