The Chelon reptilians seem to be native. The Vulcanoid Rigellians are also canon, in the person of Safranski, presumably another offshoot culture from Vulcan's sunering period, as are the Kaylar. The AU novella "A Less Perfect Union" seems to set a limit: "[T]he Earth government support[ed] the inhabitants of Rigel IV in dominating the Chelon and later they supported the Kaylar in actions against the other two dominant species after peace talks emerged between them as well as the two races getting aggressive over Earth dominating their politics." The Mangels/Martin novella set on Trill implies that the two species have a history going back to prehistory, depicting the first Trill joining to involve a Stone Age Trill humanoid. At the very least, if he was non-native he had no idea how he got there.