The Avengers would likely have a range of reactions. Captain America would respect the Incredibles' sense of justice. And the Hulk might just be confused at first but then find it cool.
If the Avengers watched The Incredibles, it could be a very interesting scenario. The Hulk might get a bit jealous seeing Mr. Incredible's strength at first. Black Widow would notice how Mrs. Incredible manages to be a great mother and a superhero at the same time. Hawkeye would be interested in the archery skills of any character in the movie who might use a bow. And they all could learn something about teamwork from the family's dynamic in the movie.
Not necessarily. 'Louder Than Bombs' could draw inspiration from real-life situations but might have fictionalized parts for dramatic effect and storytelling purposes.
Making bombs for Hitler is fictional. History doesn't document such a specific and targeted activity. Fictional stories can create all kinds of unlikely or extreme situations for entertainment or to convey certain themes, but this one doesn't align with real events.