In Hard Mode, Big appears clutching on the money fan on front of it instead.
In the Switch room, yellow area, put the sunglasses close to the "B" block sign on the front edge. Rouge's Treasure Scope upgrade can be found in this level, though the Iron Boots and Mystic Melody will usually be a prerequisite to finding it.
Red floor, B block: Inside a package Rouge can pick up, after opening the upper row safe just to the left of the falling weight (when looking at the wall of safes).
Red floor, C block: Inside a package Rouge can pick up, in the open safe from the central group of C block safes.
Big is seen under the floor, holding onto the wall below.