I agree with a lot of what you say about the photon's wave and particle duality, both the intuitive and the non-intuitive descriptions.

I do not have all the answers to the questions that you pose either.
But I have a hypothesis that may answer some of the questions or at least gives a different perspective that may eventually lead to the correct answers.

It is interesting that from the overly simplistic view point, you are voting in favor of the "push" or pressure idea as being the one that controls the conglomerates of mass and makes them fall towards each other, and I am voting that the "suction" or vacuum idea is the one responsible for such action.

Perhaps both ideas have merit, if there is a vacuum then there must be a difference in density and therefore a difference in pressure.

But then, if we consider the outer space as being an empty area or a vacuum and that the atmosphere has pressure, then it becomes a valid question to ask, why the atmosphere does not disappear into the vacuum of space, why does it stay in the vicinity of a planet?

To answer that question we take the easy way out and say that there is a force that causes that phenomenon, then we name the force and call it gravity or some other name that refers to the observed effect.

Then that word is used as an explanation of the effect, yet that word does not explain why the effect takes place.

I suspect that the why answer can be deduced from the general gas and other fluid laws figured out by Boyle, Charles, Bernoulli and others.
The formulas such as P1 v 1/T1= P2V2/T2 and p + qv2/2 + qgy = constant, may be the fundamental equations that contain the why of gravitational effects.

Perhaps all we need to do is figure out what the fundamental or quantum theory values are for the fluid of space and mass.

You said:
"It raises questions I think, about a quantum theory of gravity, but not religion."

Religion is based on faith and even scientists must at some point or another rely on faith, simply because there is not enough information to prove an assumption one way or another.

For instance take the assumption that, mass and space has existed forever and will continue to do so.

Is there any proof that this is so, if not, then we may take it on faith that it is so, otherwise we are forced to look for alternative explanations which also may need to be taken on faith. Unless it can be proven to be true, it must be based on faith.

Sort of like: RL thinks that I have no education, but he can not prove that, therefore he is acting on faith, since he seems to have followers, it also has become a religion. ;-)

Sorry, could not resist that.:-)

Johannes