Sorry for bumping my own repeatedly..
I discovered a workaround is to move the created PZ2  (not CR2, typo above) pose file to the "Expression" library as an FC2 file, delete the XMP file, and hand edit slightly, and now it works to actually apply a full pose with IK on, quickly and without problems.

The hand edit is removing the second top-level document partition, just combining them and letting the I target actors be defined twice..The 2nd version of the IK targets have the correct position parameters, so they're applied properly.