I assume that they did not make a design change in the later cars. At one of the rear corners you need to pinch the headliner to get a grip. Then you try to hyperextend that corner. That will develop some slack at the corner and you will be able to draw the tucked in edge down. Once it is started you simply continue on along the edge until you have enough of it down to have work room. It might help to use your fingers to push towards the corner on the edges to try to bunch up a little slack before pinching and and extending the corner. It is easy to get it back into place once you see how it is held in place.

Can't help you on the "extra wire" question. Perhaps the previous owner ran some auxilary wire instead of repairing the broken one?

Randy