Thanks for going into such detail 
I enjoy hearing about how other people’s minds function.
I think I understand. I too visualize by remixing and combining things I have seen, but it sounds like you have a sharper image in your head than I do. I see new remixed images in my head as if I’m seeing the whole thing through my peripheral vision. It’s like any short clip from the AI art video you linked, but blurry (moving AI art from ”バーバパパ”). On the other hand, when visualizing a remembered image, I’ll have a flash of clarity that quickly dissolves into an indistinct oscillating blur, which is more strictly defined than a new remixed image. I can re-experience the flash, but the details don’t become any clearer. In either case, recall or remix, by sketching (3d or 2d) or intensely concentrating on defining the details I can bring the image into focus. As such, it takes a lot of effort and I’m also lazy, so it’s difficult to make myself do it.
With my recent 3d art, sometimes I’ve sketchily drawn out scenes first, such as the scene from my initial sketchbook post. And in other instances, I’ve done things in a more free-form manner: start with a basic idea or object and see what I come up with as I go.
A few things popped into my head while reading your Dreams section.
First:
Do you experience your mind storage library as a visual in your mind? If so, can you go to a certain location and retrieve a certain memory? Is the location static and the process for retrieving it repeatable?
Second:
It sounds like you might be lucid dreaming. Is that the case? I’ve heard that lucid dreaming lessens the quality of ones sleep. I have never done it myself, but at times I’ve wanted to try it. I only occasionally remember my dreams.
I agree, consciously focusing on how real things work and look, then transferring that to the mind’s eye is good practice for artists. I’ve have not done that with such a specific purpose. I will try that. It’s important that the things one creates appear realistically functional. And it should help direct the visual imagination to be more functionally accurate.
I have never gone through a conscious comprehensive memory organization process. It’s an interesting idea, if a bit daunting at this point.