This could be a good idea for some skateboarding replays or any mods that have moving object in it. You just have to press a key or maybe a shortcut keys to enable it, then you move the camera to an object you want and it'll stick there.
Sorry, i don't have any example video for this one, i can't find any :/

Maybe could be made like a trigger camera, that could be set to a especific object made on the mod maker, and as you said, thare shoulder be a activation key that allows you to use that camera.

(Also, you can put some vídeo of those rc mini cars with cameras on it's top, i think those are a nice example. If i'm not wrong 'bout your idea)

You can already essentially do that with key frames I think. Are you talking a static or nonstatic object?

I’m kind of struggling to see the use without an example

just found one, kinda bad but you can understand what i'm saying

about the keyframe you said, i don't think that'd be a good idea, you'll have to keyframe it frame by frame

Im guessing you mean similar to how pressing 3 and 4 puts your camera perspective inside Tori or uke, but not necessarily following an object, it could stay at a fixed angle

Actually tori & uke cameras are static and only shows the tori & uke view, maybe could be made with 2 modes (static and following some), static could be like the freecam fixed un one point and and following could be added with the new checkpoint stuff (freerun frenzy checkpoint thing) looking to some object of direction idk