In this model, the the I/O board cable must also be removed to gain access to the microphone connector. See the upper case replacement guide for removing this part.
Also, the wire has no retaining clip in this model.
This photograph does not match the model. The microphone has a flat ribbon cable, not a round one.
In my own MacBook Air 13" mid-2012 A1466, the microphone appears like that of the part offered for sale at the top of the page, not this image.
It's certainly necessary to remove the fan cable, as you won't be able to remove the fan in Step 10 if you don't!
My microphone appears slightly different, featuring a ribbon cable which is difficult to re-route when re-assembling.
Under no circumstances try to pull the microphone out using any pulling motion on the cable, as the microphone assembly will come apart in two pieces (as mine did), and will most likely not function on re-assembly (as mine doesn't).