Biohazard
That's a good description of the thin wire function. There are none of those in the upper rear seat but they are in the rear bottom and both parts of the buckets.
I can explain why cotton batting and burlap (or any loose woven fabric) is the right way for this particular piece but it's not really relevant at this point since the piece is stuffed and wrapped.
I never dug deep into the bench seat kit until I actually started working with the burlap and batting but it actually includes a fair amount of that paper coated wire which I will have to have for the bottom cushion.
Feels good having such a large piece of progress on my bench but there's still quite a bit more to do on this particular piece.