For aesthetic reasons as well as our planned use case, I'd rather sacrifice sound isolation than close the back of the "theater" (I probably don't deserve to use that term with the blasphemy I'm perpetrating). Plus I'll save money on clips, GG, and extra drywall.
I am interested in why you ask about 4 seats as a single row. That configuration is certainly available. With the width of the screen, the outboard seats would be partially outside the edge of the screen - hence the plan to angle them back in.