From Netflix's website (help.netflix.com/en/node/100386), I quote:
"If you have an idea, script, screenplay, or production already in development that you’d like to pitch to Netflix, you should work through a licensed literary agent, producer, attorney, manager, or entertainment executive who already has a relationship with Netflix.
"If you do not have any of these resources available, Netflix will be unable to accept your unsolicited submission."
"Spam spam spam spam! Wonderful spam! Lovely spam!"
Good lord, we need a way to report spammers like this.
You probably can't in this case, if I'm reading you correctly. You might seek a "fair use" exemption (but that never means that you can just do whatever you want with other people's material), but even then the copyright owner can sue you -- and there's no way to know how the axe will fall until your name's already on the chopping block. A distributor will want to see documentation that you have permission to use others' clips.
For permission, contact the TV channel or programme you want to use.
You will almost certainly need permits; these cost money, and you aren't guaranteed to get approval. You might try guerrilla shooting nonetheless, but then you risk getting thrown out before your scene is done. You may also have problems if it's a popular spot, because you can't just use passers-by as "free extras" without their permission and you can't ask them move on; they have just as much right to be there as you do.
So ... unless it's intrinsic to the scene, it's better avoided.
There are lots of people who will take your money to read and critique your scripts. Only you can decide if it's worth your cash; if you find an incisive, articulate critic, you might find their comments helpful.
Cheaper would be to find a screenwriters' group in your area. Look for writers' societies or Meetup.com groups.