Regarding bvhmixer3, the script ran and reported processing over 5,000 frames although there are only 75 frames in the bvh. The script stopped processing frames on its own accord just above 5,000. No error message appeared.

When I played the animation only certain body parts moved, though. For example, the hips down remained in the stationary zero position. However, the Figure was positioned correctly at floor level throughout.

The really exciting news is that I typed out the DropToFloor Python script as per your instructions AND IT WORKED!

The Figure Dropped to Floor throughout the entire range of 75 frames in the bvh and the animation played perfectly.

And I am giddy with a sense of accomplishment.

This little script is going to save me (and others) hours and hours of time.

Thanks, Ockham.