Solomon Grundy is revealed to be the ISA member who murdered Rex and Wendi Tyler.
In what appears to be a homage, Rick & Beth also made their costumed comics debut together in Infinity Inc #21 from 1985.
Wearing the Dr. Mid-Nite goggles, Beth could instantly acquire information on whatever she looked at. As she tested the goggles in Courtney's bedroom, she looked at a bulletin board full of photos, including one of a young Courtney Whitmore with Santa Claus. The goggles identified Courtney for who she was but brought up a curious prompt regarding Santa Claus, "SANTA CLAUS (IMPERSONATOR?)" While it's possible that the original Dr. Mid-Nite programmed his glasses to identify people in costume, there is another possibility: Santa Claus is real, the JSA had encountered him before, and Dr. Mid-Nite programmed his goggles so he could be sure of identifying the real Saint Nick among his helpers. This is a not so ludicrous suggestion as one might think, given the long history Santa Claus has of working alongside superheroes in the DC Comics universe. Santa once stepped in to save the Justice League from the demon Neron, taking advantage of Neron's one weakness; he couldn't accept a gift without giving something in return, and Santa's powers prevented him from not giving someone what they wanted, free of charge. Santa also once battled the intergalactic bounty hunter Lobo and held his own against the Main Man in Mortal Kombat. It was also revealed in one story that Santa Claus travels to Apokolips every year to give the New God of tyranny Darkseid a lump of coal.
In the comics, Isaac Bowin is the original Fiddler. Although he has white hair, he is British rather than Irish as Pat states. After he was killed, his fiddle was appropriated by a female comic book villainess named Virtuoso, who bears a resemblance to Principal Bowin. She comes from India, where Isaac Bowin gained his powers from a fakir.
Geoff Johns explained why he introduced two polar opposites in the same episode by saying, "Hourman stumbles into his power and the addictive histories with that character is interesting. On the opposite side, you have Dr. Mid-Nite, who is cerebral, intellectual. I always found that pairing interesting in the comics, but it was never explored. It was always on the surface."