Can I use animated (boned) meshes
No. You can blame Blitz for this.
control size / rotation over time
Yes.
These all have radius etc settings, right?
Sphere, ring, and cylinder have radius (and 'inner radius', so you can have a sortof ring for those as well) settings, for cube it's 'range', or 'width, depth, and height'.
Can sphere be ellipsoid?
Not at the moment, but all it takes is the addition of an extra function argument, so you might as well consider that a 'yes'.