The F-111 was meant to be capable of acting as a fighter, strategic bombing, tactical attack, and it was intended to be carrier based as well. In practice it was to big and heavy for carrier use, too short legged for strategic roles, and too unmaneuverable for the fighter role.
Has any aircraft with two crew members side by side ever been successful in air combat maneuvering exercises?
No strategic role. Riiiiiight.
Military Deterrence of International Terrorism: An Evaluation of Operation El Dorado Canyon | Office of Justice Programs
Page details technical specifications, development, and operational history of the General Dynamics / Grumman EF-111 Raven including pictures.
So much so, that the USAF (that well known bunch of idiots when it comes to strategic strike) operated 340 of the things.