Since they are faces and they go through the crowds during entrances will they give them a high five or a hand shake?
I would go with disposable ones. I think if you get reusable ones they're much harder to clean. As for the coupler, you don't have to but if you decide to change the decorating tip on a certain bag of icing, you really cant because the coupler holds the decorating tip so if you want to change it, you just twist it off and apply a new one. I don't have couplers, but i guess its Okay. Just make sure you have the right bag of frosting with the right tip that way you don't make a mistake. Hope i helped :] Good Luck with your cake! :)
STOP, DROP, AND ROLL. Although water, dirt, or a fire extinguisher works too. You just shouldn't try to put out a grease fire with water. This mostly only happens on the stove at home.
I prefer the disposable bags, and have a separate set of fittings.