Can I plug these into a Smart outlet and setup a routine where a motion sensor is tripped, the lights dim, death metal starts playing, and then 4 of these fire off? Because if so, daddy is going shopping tonight.
You can, but it's not quite so trivial. You likely will need a little button pusher, rather than a smart outlet. The plus side is you can use cheaper air fresheners, and get far more impressive fireballs.
Shouldn't be an issue, all children's clothes are flame retardant.
Edit: I apparently got a mod report on this. The joke is that OP is like a teenager (a child), because this probably wouldn't be cool for most typical adults, and children's clothes are flame retardant by law. I'm not saying children were abused in any way, just that OP is doing a childish thing. I hope that's clear.