.....when it states "leather inserts?" Is it just the middle part of the seat??

 

Wrong button was click happy sorry, but the full seats are not leather even on "leather seats" just the seating face.

 

Does that mean just the perforated middle section only? And I have read the back seats are all vinyl, is that correct?

 

not just the perforated middle sections, the entire seating surface.
the sides of the seats & backs (meaning what faces the back seat) are vinyl

edit: pretty much all cars too, even Mercedes
and not just cars, sofas, chairs, la-z-boys.. etc

 

The front of the side bolsters are also vinyl. I wore through the seam at less than 3000 miles. ford replaced the seat cover under warranty so all is good.