Erikari showed how you can use skin constraints to move bones by applying a skin. You could also move, rotate, scale, etc bones with code at runtime. If you want bigger in all directions, just scaling the root bone is easiest. As mentioned, you can also scale individual bones. However you manipulate the bones, it will work the same even if the character is not animated.
You don't usually want to use deform keys on meshes. It's better to weight them to bones, then move the bones. This is because each deform key stores all the vertices for each bone the mesh is bound to (eg 100 vertices weighted to 6 bones means each deform key stores 600 values), and each of those vertices needs to be interpolated to compute its position between keys. By using bones to deform the meshes via weights, you only need to key the bones, which is much less data and processing. Also you can swap out the mesh with a different weighted mesh and still benefit from the bone movements (or bone positions in your case, if you don't animate the bones).
BTW, your image links are broken (private).