Movies and TV shows are a really exciting topic. But first to your questions: You are totally right, I can't recall a scene from a movie with all the details. I couldn't paint it, as I'm not seeing it like when it's right in front of me (in the movie). But I could definitely describe it and it will sound indistinguishable from what you would describe, the difference is that I'm remembering the description and you are remembering the scene itself.

Rewatching a movie is the same, I remember seeing the movie and I also remember all the scenes (the ones I remember); you might remember a scene by color and "images", I remember it by description or concept. But the result is the same: I remember having seen it.

A really nice perk (for me) is that I don't remember the individual actors. I remember the role played, but not who has played it. It's not like I cannot distinguish actors from another, but I just don't remember actor X played this and that role. I really don't understand the problems with changing actors in sequels, it's the same role; maybe played a little bit different, but still the same role.

I know a total of maybe 5 to 10 actors which I recognize among different movies.