Why not string theory? Because enough is enough

I've got to say, that comes across as awfully dismissive toward a whole lot of very thoughtful people. I'm not entirely sure what you mean by it. Certainly all of the string theorists I've known (it's my profession) have talked as if they believed their work was involved in a "genuine attempt" to model reality.

Maybe a physicist can make a living by just "doing math and writing papers" without any expectation of making meaningful progress toward understanding the world, but the people who really drive the field and get noticed are almost invariably folks who dream of changing the world, of being the next Hawking or Witten or even the next Einstein. If someone like that doesn't have the a pretty solid hope that what they're working on is likely to be truly relevant to reality, they work on something else.

I think that others have already more or less answered your electron question. I might answer it this way: one of the great triumphs of 20th century physics was the realization that the details of how physics works on very small scales (or equivalently, very high energies) get very predictably "blurred out" when phenomena are measured at longer scales (or lower energies). The formal process involved is called "renormalization", and the punchline here is that essentially any ultimate theory of nature (whether that's string theory or something else) will reduce to an ordinary quantum field theory (with "renormalizable" fields) once you get a few orders of magnitude below its intrinsic scale.

That means in particular that any "stringy" physics (or any "loopy" physics, or even any simpler "grand unification" physics) will inescapably be completely washed out and undetectable when electrons interact from a few cm apart. All you need to understand is "simple" quantum electrodynamics, in which the two electrons exert a repulsive force on each other by way of their interactions with the surrounding electromagnetic field: interactions that can be described as being mediated by exchange of virtual photons as force-carrying particles.

For that calculation, it's not at all important to know that (e.g.) each electron is an extremely tiny string in a specific vibration mode, nor that they (more or less) emit and absorb virtual photons by pinching off into new tiny strings or in a different specific vibration mode and then joining back up with them in a uniquely determined way. (This would be a good place for me to note that nobody knows exactly which scenario in string theory would correspond to our world, so nobody actually knows exactly what vibration mode corresponds to an electron. But we know a lot of ways in which things like that might work.) My point here is just that most of the questions you've asked are really quantum field theory questions: the string theory connection is almost entirely unimportant in that regime.

    (Perhaps a bit self-serving for me).

The magnetic force is just an aspect of the electromagnetic force ("interaction" is the word more commonly used in quantum field theory), so yes.

> Are charged particles constantly sending a continuous stream of photons out in all directions?

Virtual photons, yes; they aren't observed directly, only their effects--what we see as the electromagnetic interaction between charged objects--are observed. At least, that's one way of (heuristically) looking at what is happening. This way of looking at it has limitations, but it can be helpful.

Let's say I propose that no existing solar panel designs respond to artificial light. Easily falsifiable. Say you perform the experiment and find that panels from First Solar do respond to artificial light. I refine my hypothesis to "no existing solar panel designs respond to artificial light except for First Solar". You find that SunEdison panels do, by testing at your lab in SF. I refine my hypothesis to "no existing solar panel designs respond to artificial light when tested outside San Francisco except for First Solar". You repeat the experiment in San Jose, and I refine my hypothesis again.

We're revising the model, keeping it falsifiable, and keeping it consistent with existing evidence. It would not be without merit to claim that this is something of a toy hypothesis, however, and that our time would be better served otherwise.