According to showrunner Caroline Dries, the idea for the Candy Lady had been batting around the writers' room since Season 1. "The idea of the Candy Lady came straight out of the warped mind of [episode writer] Ebony Gilbert", but they scrapped the plans for her to go against Kate Kane because they didn't come off as personal enough.
When Ryan and Mary go to the comic book shop, an issue of DC's Green Lantern Corps: Edge of Oblivion can be seen on the rack. This continues the Arrowverse trend of teasing the existence of Green Lantern, although confusingly this suggests that the Green Lanterns are fictional characters in this universe.