Not in Pure RAS, because the right elbow replaces the left shoulder as the swing center. Adding a right forearm throwing motion to a left shoulder centered swing using the muscles of the right forearm, is what most people consider to be an RAS, and that does use #4.
Yes. The more the merrier. The Right Elbow doesn't Power the Flat Left Wrist Rotation through Impact.
Both the Left Arm and Right Arm Swinger include an Intact Right Forearm Wedge through Impact.
If the Left Wrist breaks Down (bends), then the Right Elbow controls both the Clubface Rotation and Clubhead Path. "Right Arm Swinger".
If the Left Wrist remains Flat through Impact, then the Left Shoulder Hinge Pin will control Clubface Alignment and the Right Elbow the Clubhead. "Left Arm Swinger".