This is way too complicated and incomplete at the same time. Children can be subpoenaed to testify in court hearings. The fact that they are young just means they are supposed to be treated appropriate for their age. But they are ALSO entitled to have their own attorney (at your cost I'm afraid unless there are special circumstances). As to when they have to appear, again this is something that is usually worked out dependent on everyone's schedules but sometimes court hearings require specific attendance. You can try this on your own but it sounds like you could use an attorney's help to make your way through the system.
