Grasping at straws here but....I've also ordered a new PCV valve in case that's operating intermittently, my theory being, it sticks and then opens and allows a slug of
oil rich vapor into the intake, hence the single large cloud of blue smoke. The over pressurization of the crankcase could also be responsible for the
oil leaks.
Unfortunately this doesn't explain the misfire under part throttle, but it's only a $2.99 part, so I may as well change it....