Those remaining triangles reminded me of something, and I eventually tracked it down - a simple shaded view (that's the picture included with this post) in Blender looks a bit odd directly above those triangles. Maybe a complete red herring though.

I hadn't even thought of just importing the .obj. It gives a rather different result from loading via the .pp2. Does that hint that there's something wrong in the .pp2 as well - it wouldn't surprise me!   :oS

Regarding the sharp edges: I assume that it's an either/or choice - either split the vertices, or bevel the edges?

Time to go and rest my brain for a while - thanks to everybody for the advice so far

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The 3Dcheapskate* occasionally posts sensible stuff. Usually by accident.
And it usually uses Poser 11, with units set to inches. Except when it's using Poser 6 or PP2014, or when its units are set to PNU.

*also available in ShareCG, DAZ, and HiveWire3D flavours (the DeviantArt and CGBytes flavour have been discontinued).