I would offer up Plaza de Toros. The clarinets are not split, the kids usually love it. It's probably too easy for your percussion, but someone gets to play castanets! It's a grade 1, but you can hide meh clarinet. It sounds like you have great trumpets, they'll love being matadors. Low brass are basically unison, so you're not spreading them too thin. You can at least read it as a SR practice piece.