Schala appears when you defeat Lavos with the Chrono Cross by doing the music thing, which I obviously did cause it's awesome. And Kid is Schala's daughter or something like that. Lucca adopted her (Kid) and some other kids and then Lynx came and burned the house where Lucca died. It isn't really chibi-like versions but mostly kids, you see Crono, Marle and Lucca as kids in Chronopolis right next to the Bell from Guardia.