The thing is it never will or can line up. The only way it would work is if you left a equal space on all sides of the center character. But then he would be levitating inside the green guy. But since the feet of the shell and the base guy have to be even with the floor. The perspective get all messed up. I.E. the outer characters legs are longer as well a wider and deeper. The easiest way to do what you need is to not sweat the exact proportions of the outer shape. Do not scale the outer guy exactly the same in all directions. Of course since the pose has multiple items living in different planes this gets tricky. Since the outer shell does not have to be perfect and seamless. I suggest you ungroup the outer shell. And build it onto the central character peice by peice. Resize each leg, arm, sword etc. Speerately over the central character. Tis could take a to of time but it will work where working the entire outer shell as one object can not work.