N2P,
Have done a small amount of filming - with permissions - for professional broadcasters.
For sound, a small mic in the headset cup is great. Picks up what you say, and your instructor, ATC etc. And the headset cuts out a lot of background noise!
However: we, like most other flying schools, ban the use of go-pros etc by students. A standard camera/phone on a lanyard is good, for taking those amazing shots where the view is so fab you have to stop the lesson for a moment, take a breath and just enjoy being in the air.
Why the ban:
First: the safe fixing of them. And the paperwork required.
Second: people lie! Or to be diplomatic, their intentions change suddenly and unexpectedly! So that private video ends up on youtube, being shared around the clubroom, or that favour (in private, it will really help me!) becomes public chat in the clubroom. So we don't do any of that.
Third: we run a flying school. Our key staff are out instructors. Some just don't like seeing themselves on a camera. It distracts them - so the student gets a worse service. And our priority is to give a student the best service. Most problems are there to be sorted out in the air - we are a flying school. At least the handling ones.
The big problems are students who don't do adequate look outs. Don't remember checks. etc. Again, you don't need a CCTV to point to to say to the students: I never saw your head turn. Or state what each letter in a mnemonic stands for - or even what the funny word is.
A final point: what do you point the camera at?
To me, that is the beauty of a flight simulator. You can freeze, go back 30 sec etc. So you can choose which bits to focus on. We don't have one - yet. But we are working on it.
N2P - get a few hours in the air and come back and tell us a few things.