Sorry, you can't add a microphone, this digital camera was built-in microphone. 

I guess your Macbook Air port is Type-C port, there are following ways for you: Way 1: need a USB A to USB C adapter. If your computer is type-c port, you need to have a USB A to USB C adapter, use the equipped usb cable, type-C end of USB cable to connect the camera, another end of USB Cable (usb-A) to connect the USB A to USB C adapter, and then insert into your computer, you will see a U disk icon on your computer, and then you can transfer the phones and videos on your computer. Way 2: Need a usb c sd card reader for Micro SD/SDXC/SDHC. We hope it is helpful to you. Thanks for your kind asking 

Yes there's a port on the side for the plug in & the mic slides on top 

Yes,it is 

Ideally you want to be no more than an arm's length away.