Wow, this is an extraordinarily sophisticated set of questions. i'll just try to get you started on the answers.
First, as background, there's nothing special about light in this regard. All 'particles' are represented by fields which obey wave equations, yet under some circumstances show particle-like behavior. Both electrons and neutrons have been shown to exhibit wave-like properties in interference experiments.
As for your final questions, we routinely measure individual photon blips from ordinary light sources using devices such as photomultiplier tubes. For a change, by 'we' I really mean including myself, not just the collective scientific 'we'. So it really is easy and routine. As for preparing single photons, that too can be done, less routinely, with solid-state devices driven by single electrons. Of course you could also think of gamma rays from a radioactive source as single photons.
Now for the core of your question, concerning the interpretation of quantum mechanics. This won't be so easy. There really is no point in any of these processes where we need to represent the physical state with anything like a classical particle. At every point we can represent the whole thing with a quantum wave. Under circumstances where some large thing (a needle, your brain...) ends up in a different state depending on where that wave goes, we only see one of the possible outcomes- as if the other parts of the wave disappeared. So if you set up some sort of detector which is sensitive to where the wave hits, the outcome we see looks like the wave got localized in one little almost-particle-like region.
How that happens, and whether the rest of the wave disappears or joins other versions of us in other versions of reality remain hotly discussed issues among physicists and philosophers. Meanwhile, the old 'particle-wave' issue as such has pretty much gone away.
(published on 10/22/2007)