Hi guys,
Don't know if this has already been posted and I apologize if it has.
Just thought I'd share my fix for the mysterious hatch area rattle. It was caused by the latch actuator assembly. It contains loose plastic gears that rattle against the housing and each other. The fix is extremely easy. Just remove the actuator assembly from the car, open it up by removing the cover and add copious amounts of sticky grease on the main plastic gear and small motor gear. The grease will keep the gears from rattling inside the housing. Re-install it and it will solve 99% of all hatch rattles. It completely worked for me!
Check out this vid I got from Youtube. Pay attention to the part about the actuator assembly.
https://www.youtube.com/watch?v=OZ9qlU9tUHY&t=339s
This fix is especially important for anyone running an aftermarket exhaust system. This rattle was always there from new but became a serious issue for me once I installed my Ark DT-S exhaust. Hope this helps!