>>530807050
Both videos use a combination of replay mode and in-mission shots with some of the squadron intro cutscenes. If you want actual freecam, you're better off asking these guys if it's possible.
Otherwise, you could use replay mode yourself. The devs figured out how to get cool camera angles out of it as early as AC3.
https://nitter.poast.org/BelkanLoyalist
https://nitter.poast.org/Death_the_d0g