Another approach to this could be to see what the module expects to see when the sway bar is both engaged and disengaged. If an adapter can be made up that plugs into the disconnect harness that just returns the expected values. Don't know if this would be easier.
With your question with the headliner I went aftermarket with Hothead Headliner. From what I recall the price is about the same as the Ford factory headliner. Nice thing about them is they have multiple colors to choose from and the install was very easy.