I guess this depends on the type of animation you want to do while still allowing your characters to be edited.
With voxel animation, you are literally editing each animation frame like you would a cell-based 2D animation. That doesn't really work with allowing your players to edit their character, as their edits can't propagate down through all of the frames. Example: editing an outstretched arm is not the same as editing an arm down by your side.
I guess if you're looking to allow your players to edit, you're probably going to want to look into more traditional animation with Mecanim, where each part of the body is a separate volume and rigged together.
I don't have any magic in PicaVoxel for this - you will have to create the rig yourself where each body part is a Volume. You could still allow this to be editable by casting a ray out to detect which volume is being clicked/pressed on, and then changing the voxel colour at that point. There are quite a few topics here on runtime editing, by the way.