Multiple Magnificent Misters: The Other Terrific Miracles

Perhaps their worlds' greatest escape artists, with the Batmen as strong contenders, Scott Free and Terry Sloane used their varied abilities as costumed crimefighters. While they were the most famous versions of Mister Miracle and Mister Terrific, respectively, they were not the only ones. Two other men assumed their alter egos on occasion, 

After Scott escaped the planet of Apokolips, where he'd been raised in an adversarial orphanage ran by Granny Goodness, he began a new career as a performing escape artist on Earth-One. Trained by the expert escapologist  Thaddeus Brown, Free assumed Brown's professional alias of Mister Miracle shortly after Brown's death. In time, Scott likewise trained his young protegee Shilo Norman, who had likewise escaped an orphanage and sought a new life.

While Terry had a lengthy career during the 1940's as Mister Terrific, the "Man of a Thousand Talents" who was also known as the "Defender of Fair Play", on occasion he too enlisted the aid of other men to assume his alter ego. These included violinist Ivanovitch Bizochki, heavyweight fighter Harry Magee, and an unnamed electric science expert. But was this the only time that Sloane had others substitute for himself, or was there occasion years later in the 1970s when another took his place?

In fact, when Mister Terrific joined his fellow Justice Society of America members aboard the Justice League satellite in October 1979 during their annual meeting, it was noted that the last time Terry appeared with his allies was in August 1965, during the Black Spheres case*. However, in August 1967, a Mister Terrific along with the Society traveled to Earth-A to combat the Lawless League. Since this adventure was erased from history by Johnny Thunder's Thunderbolt, as he initially created that world under duress under orders of Johnny's evil counterpart, this tale wouldn't count. 

However, Terrific again appeared along with the Justice Society when they battled T.O. Morrow and accepted Red Tornado as a member in August 1968, then attended JSA meeting the next year during the Creator2 invasion.  In September 1972, Mister Terrific once more had an active role, aiding the Society in helping to locate the Seven Soldiers of Victory and their lost eighth member. So who was this hero? Might he have possibly been one of Mister Terrific's stand-ins, who had the physicality to take Terry's place, as Sloane had by then retired as advancing age creeped up on him? Or was it Terry, still going strong in his late 50s?

* The letter column of Justice League of America #176 corrects this mistake, acknowledging Mister Terrific’s later adventures between the Black Sphere case and the hero’s untimely demise.