Sun Dance - Ticheli

Mock Morris or Themes from Green Bushes - Grainger - but if your clarinets are weak, likely you should avoid.

Maybe Khan by Giroux?

However - if you're concerned about endurance, perhaps selecting one of the pieces on the Grade IV list that have multiple smaller sections, such as Scenes from the Louvre, might be a good bet? Your kids can take a few breaks in between movements.