Be sure to remove the film over the new microphone before sliding on the rubber cover! I missed it the first few times and could not understand — for the life of me — why the microphone wasn't working. It's easy to miss!
I used a single Phillips screwdriver for all of the Phillips head screws, and a single flathead screwdriver for the flat head screw.
I broke 2 of the 4 off (both on the left side) and haven't noticed any difference in the functioning of the phone.