Gender reveal plans?

Mamaof4 • 4 kids ages 11, 10, 9 and 2 years old.
Hubby and I are doing our gender reveal at our Halloween party. We decided to be pranksters and do the typical ideas but not reveal anything. (I.e. Silly string that is green, balloons with orange confetti, box full of white balloons, cupcakes with chocolate centers...) then after reading a bit have him say "Ok well we are having a... " and then I'll blow a bubble (using gum) with either pink or blue to reveal it. ;) My family and friends are driving us nuts about telling "just them" early. (We are finding out the day before the party)