Guy Gardner and Billings were the stand-ins for the original Green Lanterns, assisting the pair one a few occasions by dressing up as them, although they each had short-lived careers as costumed crusaders.
Hal Jordan as Green Lantern saved school teacher Guy Gardner while Guy was himself saving a scared girl from the collapse of a bridge. Gardner developed a romantic relationship with Kari Limbo, one that would not last the test of time. Guy's forestalled career as Lantern's ended quickly in tragedy. Caught in a power battery discharge, Gardner was sent to the Phantom Zone, after which he was eventually freed and returned to Earth-One by Jordan. The experience left Guy mentally traumatized. Gardner would later be revived and then granted the power and title of a Green Lantern once more during the Crisis on Infinite Earths, given a mission to lead an army of supervillains to the Anti-Matter Universe to defeat its leader the Anti-Monitor. The fact that Jordan had started dating Kari while Guy was in the Zone led to enmity between the two Lanterns that persisted for years.
Alan Scott as Green Lantern learned that his predecessor to the power battery, given to him by a monk, was a former businessman named Mister Billings. When the stock market crashed, Billings lost all his wealth and blamed his investor whom he slew. Incarcerated in Arkham Asylum in Gotham City, he was given the ancient Chinese lantern crafted by Chang from a Green Flame meteor. Refashioning is as a modern battery, it flamed and restored Billings sanity. He then presumably returned to a normal life. Whether Billings later met with Scott is unknown, as he was an old man when the Green Lantern debuted in the early 1940's.