Азгалор
First, I'll answer the latest questions:
1. Selecting an object + Ctrl rotates the object towards the cursor. If you hold and move the cursor, the object will smoothly rotate along with it.
2. What do you mean by "didn't stretch"?
3. RelativeCamera and Actor – this is for attaching the camera to an actor. It works through a certain method (or rather, it doesn't work), so don't use it.
4. It seems that MovementSpeed only works when viewed in the game.
Now, the main question.
How did you work with the video? Like in my latest guide, or the first one?
Don't touch the map and videos yet if you want to be able to restore them. Depending on how you worked and what you did, it determines where the "latest" version of the video is located.
1. Thank you.
2. Like this (13th block/stage/step, I don't know what to call these elements). I have a couple of these "defective" cameras in the scene (and, of course, because of file corruption, the editor no longer sees them, but I set them up through a workaround and everything is fine), which break the view. But as I understand it, the view is restored if there is a transition to a normal camera after such a camera. Probably, all this happens because of the RelativeCamera and Actor settings in the camera.
3. I understand. I tested it, and the camera with this setting seems to be slightly pulled towards the selected "actor".
4. Aha, that's what it is... Well, okay, I'll keep that in mind.
No, not at all. I've already started working on the video, and then I decided to check out your updated guide with Arantir and vampires. I'm working on the video, and at the same time, I'm also refining the map for which the video is intended, and now I make a backup of the entire scene folder after any major changes to the video files so that I can restore it later, so it's not really a problem for me anymore. 
And again, I have no idea about the latest version. The video files are located in the files of the map being developed.