Its pretty clear why the elevator is involved. Both the facade and queue feature the destroyed elevator shafts. Then the movie tells us the backstory. As for the people, its pretty clear they are 1930's hotel guests. And of course the video is necessary to the attraction, that's why it is included. Its not something in the background, its a room we all stop in for the experience. Luckily, the video does a great job of "show not tell" with the images telling the story rather than having to rely on the words. If you spoke another language, you'd still be able to follow the backstory 100%. With the current layover, its very reliant on dialogue and the video doesn't show all much.