Sounds like you have pretty much worked it out with OB, but personally, as I've overly assertive, and sometime aggressive, I'd call her and tell her she's fired. That's just me.
My questions are, are you still worried about any of the stuff (misconceptions, lies, etc) she said about the u/s? If you are, then I would address them with your MW, Doula, or other supportive people. This is what I think, size doesn't matter of the baby, and this late in pregnancy, with the size given, I wouldn't trust it. U/S is more accurate is judging size if the baby of of average weight, but bigger and smaller babies are usually off by lbs. Anterior placenta, don't worry about, and there are really no studies that show it makes a difference in labor or birth. Fluid levels, this could be due to not enough fluids, or the fact that the baby has yet to pee, and probably did so right after the u/s. Your body has a way to, if something isn't going right, it will go into labor and get the baby out. It's in the animal instincts of self preservation and offspring preservation.
I'd see a chiro for posterior baby, and there is TONS of stuff on spinning babies.com. Rebozo jiggle, belly rubs, hands and knees, visualization, etc.
