What goes here
 

My son has a 1986 RX-7, he is wondering if these were for back seats or the storage bins.
https://cimg9.ibsrv.net/gimg/www.rx7...f2ffb300a5.jpg
https://cimg2.ibsrv.net/gimg/www.rx7...6eaaf18a6c.jpg
https://cimg3.ibsrv.net/gimg/www.rx7...0a59095e73.jpg

The space can fit both back seats or storage bins, whichever you choose.

Technically true but it should be noted that many circus performers have died trying to sit in the FC "rear seats" and countless teenage Japanese gymnasts have suffered career ending injuries making the attempt.
I once saw a six pack of beer suffer a severe sprain after being carried in the back of a FC.
So yes, FC rear seats exist, but should be treated with extreme care.

Judging by that wiring harness with bulbs still attached, your particular car had storage bins.