they are always in the other room, or at camp, or otherwise elsewhere unless required for a scene. Lulu's main storyline when she returned was to get her daughter back home. Now she's back with Lulu we never see her. Avery is talked about when Sonny and Ava are fighting for custody ... otherwise she is seldom seen.
Of all soap children, Violet got the most air time and some solid storylines. I have to give it to GH though, they do a great job casting the children. When they do show up on screen, they know their lines, connect to the person they are speaking to, and are enjoyable to watch.
Karen L.