What continuity family do the First Transformers (Jet-Kun, Racer-Kun, and Dump-Kun) belong to? What else do you know about them?
You forget that the multiverse contains infinities—and more often than not, Cybertronians are refracted and mirrored across multiple divergent branches of reality. In some realities, they are Go-Bots, who hail from Botropolis and cause trouble on various organic worlds—but over the years I have glimpsed many other incarnations of theirs. In one universe, Jet-Kun, Racer-Kun, and Dump-Kun are young Micromasters, born and raised on the colony world of Micro, and I understand that governor Riker has taken a shine to the three mischievous ‘bots, despite their myriad misadventures. In another, Jet, Racer, and Dump were among the many recruits to Autobot boot camp just before the Great War; unfortunately, they had the bad luck of winding up under the command of Impactor Minor, who saddled them with simple, utilitarian codenames.
I have seen them created in times of prosperity, and times of convalescence: emerging from the Pyramid during the Age of Expansion, selecting alternate modes and occupations of their choosing (courier, athlete, builder), contributing to a peaceful society in the time before the War of the Threefold Spark. Or as part of the first generation of Earth-born Transformers, born in the aftermath of Unicron's destruction, now happily enrolled in Arcee’s classroom in Little Cybertron. Or, thanks to Optimus Prime's sacrifice, arising from the Well of All Sparks on a renewed planet; although they and the other young ‘bots of batch 418 are currently in the care of the Autobot Cameo, Dumper the Loader-Bot, Jetset the Fly-Bot, and Racer the Zoom-Bot might one day become full-fledged Rescue Bot trainees—if they can learn to work with one another first.