You're right that Ballora, Funtime Freddy and Ennard are all not in FNaF:World, but... Baby and Funtime Foxy are both showing in FNaF:World.
And yes, I know that Funtime Foxy in FNaF:World and Funtime Foxy in Sister Location are completely different due to material built on them. So that left us with Circus Baby... her eyes showed up in the Desk Man's house when it was darkened out while she "killed" the Desk Man.
So in the result, Circus Baby is the only character from "FNaF: SL" to show up in FNaF:World...in the sight of her green eyes and her voice. >_>