Is it possible to stencil an intricate design motif on a cake so that i can then easily go over the motif with icying without much worrying about scale, centering and mistakes. If so, how can that be done? Please advice.

You could put the stencil on and use a toothpick to poke the design in the fondant then go over that with icing. Or you can put the stencil on and ice that with royal icing or buttercream, then pull the stencil off and voila! -you have your design!