Quote - Is it handling better without limits, now that the alternate foot geometry is in use?

No, but I did not want the limits interfering with the changed parameters, that might have muddied the waters, and made the results of the test harder to interprite.

Quote - I'm curious about thighLength, particularly.  The other two are obviously used by the Walk Designer only, but thighLength is included in all poses.  How is Poser using it, outside of the WD?

I don't think it is used outside of the Walk Designer. It's being written into the file in case the file is to be used in the WD. "thighLength" has been around since at least P4. I don't think feetDistance, and hipHeight existed in the original P4 version of the files that shipped with P4.