1) Have you read Gettier's paper "Is Justified True Belief Knowledge?"? I recommended it; it seems to create problems for the JTB analysis of knowledge even assuming a Bayesian understanding of "justified."

As I argued in this comment from 2011, the intuitive reaction to the Gettier scenario is based on a probability-theoretic mistake analogous to the conjunction fallacy (you might call it the "disjunction fallacy").