I don't think that seeing with your mind's eye is similar to dreaming. I heard that they involved different parts of the brain. I have aphantasia but I dream really vividly (crystal clear images and I experience all 5 senses in dreams), and they feel real, like real life.
Yeah, I think the melody and then I can hear the music/song in my head. I think that's the only sense that I can access in my head.
I have vivid dreams as well. Wdym by "internal voice?" Btw, how do you experience your thoughts? I think that I have an internal voice too, but I'm not sure. Strangely, I have a good sense of direction, I think I have like a 6th sense. Someone once said that I had like psychic abilities or something. I don't know how true that is, but I guess I'll take it just for kicks