Why would the Creator elect to create suffering for ITself?

[βαθμιαίος]

however, the characteristics of the spirit, the very differentiation in the nature of those elements, would be discovered, manifested, and carried to another octave.

I don't disagree that the gleanings of this octave are carried forward to the next. But Ra says "it would not be our awareness, but simply awareness of the Creator. In the Creator is all that there is. Therefore, this knowledge would be available."

So I agree with Quantum that the Creator carries forward what it learns in this octave, but individual entities don't do so as individuals because they have merged back into the Creator.

In this context each and every entity of consciousness has/is/will experienced/experiencing/experience each and every density.

I agree that this could be interpreted in the way you suggest, but it could also be interpreted to mean that they will experience every density because they are part of the one infinite being. Given Ra's other comments that I have posted above, I think the latter is the safer interpretation.