They are replacement covers made by TMI
Classic Automotive Interiors - Restoration and Restyling Products for Classic, Fox Body, and Late Model Mustangs
I don't believe they will work with side airbags
If your car is not a Pony Package equipped car the harness is not present.
There are countless threads on various boards on how to install an aftermarket harness with and without a factory switch.
Stangpede has four or five chapters in CA. Maybe check out the website before making a statement like "WE dont have anything out here in cali like your cars"