Thanks for your thorough post! If I may, I would like to hear what you think of the following:

Important features about the double-slit experiment are: the slit width, and the velocity of the particle (when the particles are larger such as a molecule, they must pass through smaller slits at slower speeds in order to produce an interference pattern).

What that tells us is that: diffraction is gravitational lensing. If the slit is large, the vast majority of the particles will pass through the slit at a distance from the walls of the slit that is too large to be substantially gravitationally lensed by the local gravity when passing through the slit. If the slit is sufficiently small, any slight variation in the flow pattern of the particle from the exact center of the slit will cause a local gravity variation on the particle that will arise in the observed diffraction. This would lead to a wave such as we see. If the particle is high in mass, it must travel slower so as to be exposed to the local gravity for longer so as to go from a particulate result to an interference pattern.

In this way, light is a wave of particles, in the same way as a wave in the ocean is a wave of particles. Other particles can also produce interference patterns when they are small enough in mass and/or travel slow enough to have the actual local gravity of the slit influence the trajectory of the particles.

-Steve