Not sure that you would have to remove the headliner for any part of what you are trying to accomplish. As far as it being loose you can just get the right size torx and tighten it down from the inside. Mine has been loose a couple times and it just takes a couple turns on each screw.

As far as it not working you would probably just need to get at the motor where the switch is.

Lastly the sunroof shade that you speak of installs easiest from the top without taking the sunroof or the headliner off.

Now, to answer your question... The headliner is not extremely difficult to get off. Just have to take off alot of trim pieces to get to the tabs tha hold it up. Its kindof a PITA but not horrible. Like I said above though I am not sure you will gain anything by doing this.

Chad

MODS:
3" PVC CAI, GST Muffler, Greddy 4-1 Header, AFX UDP, 55 mm bored TB, P&P Intake Manifold, Corbin intake spacer, gutted cat, Apexi S-AFC, KYB AGX Struts, Eibach Prokits, Excel TZ-10 Rims