[first.time.mum]

The two ultrasound thing is pretty standard, especially here in Toronto where the OBs are packed full (apparently more than usual this summer for some reason). They will have determined your placenta placement at your 19 week appointment, if you want to know, your OB should be able to tell you, if they were worried about it, they'd have said something and likely done another u/s.

your appts sound exactly like mine, less than 5 minutes with the doc, the nurse does half of my measurements too, he just does belly, not even hb
As far as positioning, they can tell by feel, although at 30ish weeks it can be tough to differentiate bum from head apparently. If they suspect something isn't right, they'll do follow up tests, but the standard is just those two u/s's...

I don't know what hospital you're at (I feel like you said one of the downtown ones in an earlier post) but even when I went into the hospital with abdominal trauma they didn't do an u/s, they just monitored the baby for an hour or so...