General Clutch squeaking - video attached

[xarenwo]

I think the reason is part 9 from your diagram - the spring

The Spring is on the top of the clutch master cylinder so it's there to help the return of the pedal in a smooth way, not to make the pedal come back or keep it up. If you open the clutch circuit the pedal will stay down with no resistance, the spring is there to not let the pedal get thrown back brutally by the master cylinder when the clutch pressure plate is pushing it back

 

[Sylvester22]

Under free play I mean that at beginning the pedal can be pressed without much effort, but you need more effort to press it to the bottom

There's a bit but not more than it'd be. The squeaking sounds even further up/down.
Although the colder it gets, the less noise it makes.