M4 doesn't load with any IK, so it was always off.  The head was exported with welded seams and body part names used in polygon groups.  Exporting it "As Morph Target" gives me a head that's skewed away from its proper position relative to the neck, and it's a whole mess to fix it and still have everything bend right.

Argh!  I've solved the leg problem, but at the same time I noticed that the chest gets screwy if I bend either collar.  Here's M4 with a male V4 head and his left collar bent 15 degrees Front-Back.  I never touched anything below the neck while morphing, so I'm at a loss to understand what's going on here.