It: Chapter Two will introduce a whole new cast of Losers, as the film will follow the characters into their adult lives. But we can expect to see the kids again, too.
Muschietti told IndieWire, "We are going back to the summer of 1989 and if people love these characters and actors the way I do, it's going to be a blast to go back to 1989 in the second one. I don't want to go back just for that, I want to make those flashbacks essential in the plot where in order for the Losers to figure out the clues to defeat Pennywise, they have to retrieve their memories from the past." And it's not just going to be visions from the first film they retrieve, either. He told EW that the child actors from the first pic are "a very big part of the action" in the second.
Perhaps one of the new scenes for the younger stars has already been hinted at by the director. He previously told Collider that he had to leave an eerie Bill Denbrough scene out of the final script due to budget concerns, saying, "Bill sees— he's leaning on a bridge, in Derry, and he's spitting on the Kenduskeag Stream, and suddenly he sees the reflection of a balloon. And he looks up and it's not one balloon, but a bunch of balloons, and then he starts to see body parts, and the shot goes wider and it's a multitude of dead kids floating." Now that the box office has earned the studio a massive return on the first film, he probably won't have as strict a spending limit the second time around.