You need to create your own limits of how to use copyrighted work. If what you're doing is transformative and doesn't compete directly with the market of the copyrighted work you are using, then there is the argument for Fair Use. Off course you can be sued, but that's the risk of using Copyrighted work for any case. Just make sure what you are doing is transformative and you should be fine. Unless it gets popular, then you are definitely getting sued.

For example, mash-up videos use parts of songs and musics all the time. And they are protected by Fair Use.

Just watch every video YMS (Youtube) as put out about Fair Use. It's not really that complicated to understand.

Interesting. Love how the video starts talking about consent in the professional world of cinema, but by the end it changes, and becomes something else. A narration from someone who can't tell the difference between news about a person's career, and news from their personal life. It almost seems like this video had it's own agenda.

You can't make a logical jump from what happen in "Last Tango in Paris" and consent in films, to what Woody Allen does in it's personal life, or the fact that Nate Parker is allowed to make films. That argument is a non sequitur.

Who is "they" in your comment? The Aliens? If so I don't understand what you're trying to ask.

"...he's currently directing the remake of sci-fi classic Blade Runner..." - He is directing the Sequel to Blade Runner, not the/a remake.