Okay! The only reason I ask about cold sparks is because there was a discussion elsewhere on these forums about sparks being used for the Star Wars Rise of the Resistance ride that are completely cold and pose no fire risk as they are created from non-flammable materials being combined in a machine that makes the effect. Here's a video of it, and someone interacting with it to prove the fact that it is not flammable and for indoor use!Well the electronic firecracker does have a disposable component, and they are designed for only short (few seconds at most) and not continuous bursts of discharge.
Some of the shock effects used in your video shows that it needs to be a few hundred feet/yards away from certain materials which worry me. Glad you thought about an extinguisher and a barrier to keep people away!