I'm going to just respond briefly, because I'm running a bit late for school. Read
this thread -- the wiki you posted was a bit misleading about middle knowledge; in any case, given the way I approach the problem, not having free will in the fullest sense doesn't matter. I've found that people who think that we need free will "in the fullest sense" often have trouble distinguishing free will from randomness.
Regarding knowledge, when I say JTB is the generally accepted definition of knowledge, I mean that I've never meant or heard of an analytic philosopher who disagreed with that definition. The problem you raise of a lack of second-order knowledge doesn't matter here, since it's clear we sometimes have knowledge, and we've just been stipulating as to knowledge cases. The problem of the subjective nature of justification, connected to the problem of our lack of second order knowledge isn't problematic here, since we're talking about objective justification. Finally, and I apologize for not being clear about this, but what I meant by definition was merely that JTB is a necessary condition of something's being knowledge, not a sufficient condition.