Hi @pbriggs !
A small look into the future: in 2.81 you will be able to animate a sculpt directly, no retopology or armatures necessary.
Thanks to Pablo Dobarro 2.81 comes with an Elastic Deform Brush and a Pose Brush!
Using Shapekeys on the sculpt you will be able to do amazing things! Here’s a small demo of the Elastic Deform Brush (this took me just a few seconds and the result is not great, but I only wanted to show you the power of this…):
