John,
My point about the interference pattern of the double slits is this.
You can represent the geometry of the double slits by a one-dimentional, mathematical function, with a value of zero, wherever the slits are opaque, and a value of one, where they are transparent. If you then compute the magnitude of the Fourier Transform of that function, you obtain another function, that looks just like an interference pattern.
This is purely a mathematical relationship. It has nothing to do with particles or waves striking the slits. It has nothing to do with physics. It is pure math.
The geometry of the "boundary conditions", that is, the geometry of the slits, contains almost all the information content of the observed "interference pattern", the waves or particles striking the slits merely act like waves or particles striking a bell; they induce a "response" from the bell, that in turn is detected as a sound wave. But this sound wave contains little information above either the waves/particles striking the bell, or the air that the sound wave propagates through. The vast majority of the information observed within the sound wave, is about the "normal modes of vibration" of the bell, the structure of the bell. Similarly, the "interference pattern" is mostly about the structure of the slits. By misattributing it to the waves/particles striking the slits, physicists have misinterpreted what is happening.
Your concern with energy is instructive. What exactly is energy?
I first became really interested in that question, forty years ago, when I was a graduate student in Physics. I had a teaching fellowship, which required me to teach an introductory physics lab class, designed for life-sciences majors, not physics majors. It was a required class, so the students had to take it, even though few had any real interest. One day, a student, who was a bit of a "slacker", came into my office, during "office hours" for the class. He wanted to know what energy was.
The more I tried to answer his question, the more I realized that I did not really know. Sure, I could do all the math, but what, exactly, did it really mean? Why is the fact that it is conserved (constant) significant? It finally dawned on me, many years later, that being constant, is its significance. It is its only significance. It is nothing more than a set of variables, whose combination was deliberately constructed, such that it would be a constant. There is not a physicist in the world who would care about it if it were not constant. Great "significance" has been slapped upon constants, in physics, simply because their future value is so easy to predict. But a single, constant value, contains very little information. Hence, in Physics, "significance" is directly tied to low information content phenomenon. It is a manifestation of the old line about "Knowing more and more, about less and less, until you know everything about nothing."
For an "observer", it is not so much the flow of "energy" that matters, but the flow of "symbols". Consider the old story about a butterfly flapping its wings, on the other side of the world, and thereby causing some highly unpredictable event to occur, thousands of miles away. Which do you suppose to be a more probable "cause" for such an occurrence?
1) The physical interaction of the air molecules, disturbed by the flapping wings, are transmitted (flow of energy) across the world.
2) A young girl makes a video of the butterfly, uploads it to You-Tube (flow of symbols), it goes viral, and thereby causes millions of people to stop whatever they are doing, and watch the video.
Any entity, from a hydrogen atom on up, that can change its internal structure, and thus form a "memory", can use that memory to respond to other entities "symbolically", rather than "physically". And the more memory they have, the more complicated (high information content) these responses (behaviors) may become. Physicists behave this way. The entities they prefer to study do not. Consequently, the theories they devise to explain the behaviors of the latter, are woefully inadequate at explaining the behaviors of the former. By assuming the contrary, they have misinterpreted reality.