For anyone reading, the solid state relay modules, although cool beyond my dreams, will not work for this project (at least the ones I got.) They work GREAT if you actually have 120 V on the switch side, but as confirmed by @DvDdoug in this thread, they're not just a "switch." In my initial test I tested a 120V light unit, worked great, as expected. Since the fog machine switch is just a switch,
There is (apparently) no actual current between the two switch leads. The Relays cycle along fine, sometimes it will fire on the first signal, but none after. I experimented with bursts from 500ms to a full second. To test I disconnected the relay leads and shorted them out manually, fired every time. 
So I guess it's back to mechanical relays but I don't have protective modules, investigating circuit protection as mentioned by Paul above.