Great that you elaborated on my reply so thoroughly! :)

Yes, you get it right. Your point that I insinuate "all creativity is an illusion" is correct in that actually All is Light energy which is never stagnant but always flowing and morphing. My definition of "real" is that it is unchangeable. But in fact everything is constantly changing on some level, so it can ultimately not be "real". As such, we have literally creative Freedom beyond any limitations of the word but with no lasting consequences.
And yes, Artists or authors might receive pieces of information incorrectly and/or mix them with our reality. So regarding the horror movies, no, they are not necessarily depicting a reality taking place elsewhere but the author probably connects to a place in the Universe where such entities live and then mixes them with our reality. So yes, everything has its source. We are living in a Time-Space continuum and we are constantly connecting to it whether consciously or unconsciously :)