When you go to reverse the steps it can be tricky putting the keyboard back. I turned the assembly over to be able to get to the tabs from the back side. Also make sure that you thread the backlight ribbon cable through the frame.
I fully agree with urdus. Step 11 is un-needed when replacing the harddrive.
On my iMac (20" intel core duo Model A1207) this was not a "connector" rather it was four separate (loose) wires! So I did not remove them for fear of reconnecting them in the wrong order. Instead I first loosened the drive bracket and removed its cables, then I pryed the thermal sensor from the side of the drive.