I am not sure about the fix, but it may be your left rear that is the most wrong. Front tires on rear drive cars tow in because when the chassis pushes the front tires froward it will take all the play out of the steering linkage and move toward neutral (straight ahead). Front drive (fwd) is just the opposite. The tiress are pulling the chassis so you start with tow out instead of tow in. An independant rear wheel drive (IRS), woulld be aligned like a front drive because the drive wheels are pulling the chassis along. I think you should have tow out on your rear but a negative .42 sounds way excessive. Please keep us posted on what you have to do. I would look for a frame and alignment shop rather than just an alignment shop.