Your thoughts about these communication experiences are very interesting. I'll try to add a more technical/analytical perspective, from my autistic point of view.
I think the communication happens through synchronization of brain waves and thought with what you call higher intelligence. Sort of like playing a song together.
You play your instruments (resulting in different types brain waves playing together in a special way, similar to a melody or harmony), and the "higher intelligence" orchestra plays its instruments. In some moments this orchestral arrangement/score may take the form of synchronicity, which may also act as a guide, or as a confirmation that you are connected to "higher intelligence". This may help some minds like mine to keep the right focus. Sometimes to some humans the synchronicities may seem like a "drop" in electronic dance music.
Music makes it more likely to become synchronized with the higher intelligence orchestra, when you're not in a deep trance state. But in some states of mind music is not necessary. You may even forget that there is music playing, while being fully immersed in certain layers of reality or in the dance with what you are connected with.
In my case, typically some obvious connection event happens first. Often preceded by some sort of personal ritual, game and examination, compatibility check, or something. And typically some hours later a disconnection event happens, which may be confused with a come-down. While connected, communication is possible, depending on your mind. Obviously if you're busy with your own mind (e.g. with your past or future) during that time, communication won't happen. Or your mind may be drifting/surfing in that metaphysical space, without communication. Which is probably a favourite activity of many explorers.
I also think that depending on the depth of your experience, simple things like getting up from the sofa and moving your body can break the connection.
I assumed that is because the brain waves necessary for body movement and everyday activities, like walking, may interfere with the current harmony (different types of brain waves playing together) of brain waves, and it may be difficult to re-establish the harmonic brain waves necessary for staying connected. Which is why I may avoid standing up from the sofa for some hours. Though that may also depend on various factors (e.g. dosage), and disconnections due to body movements aren't necessarily an issue.
So by removing past and future, and by turning off verbal thought and "every day brain waves" (generated by neuronal networks in our brains, which are deactivated during a psychedelic experience, I suppose), psychedelics make it possible for us to connect to "higher intelligence". Verbal thought is "too loud" and distractive, so it may make communication impossible.
There are some issues which can occur, like you assuming that there is a communication attempt while there really is none (especially when you have certain triggering songs in your playlist). But with experience you can learn to navigate properly. Or maybe you can "see" it with your inner eye. Sometimes it's really easy for us to understand things we normally wouldn't understand. But sometimes our brain may be lazy and misunderstands things.
I guess it's self-explaining that your music playlist is some sort of offering for that higher intelligence, which it can work with. But the higher intelligence utilizing the random number generator of the media player (if that's how it works anyway, I don't know how it does it) may only work when you keep your mind synchronized with the higher intelligence. Basically, when you're synchronized then every random song will be the "right one" on your path, so every seemingly random song is suitable for communication and guidance.
At least that's my impression. With my above average IQ I'm not intelligent enough to understand how it works. And I don't need to understand it.
Often I rather called it (or aspects of it) a hyper-computer, and barely ever called it higher intelligence (while indeed having the impression that there is something much more intelligent than me in action). I assumed it to be a part of the same structure which is responsible for running spacetime (laws of physics etc.). Just another layer of it, which is normally hidden for human beings, probably by an elaborate and necessary barrier or something. But for many things I'm blind, even with my inner eye being wide open. So I may be mistaken. But that makes it even more exciting, right? I'm glad I'm one of the minority of humans who have the privilege to experience the cosmos and reality this way.
Keep dancing and exploring! To boldly go where no human has gone before