LionFish says.....
That sounds like a great mix together. I've seen numerous people with large Maroon Clowns in with Puffers before. I'm not really sure with the Trigger and Clown together. But the Clown sounds big enough to handle himself. Just watch the trigger to make sure he doesn't pick on the Clown. Picasso Triggers are a bit more docile than other Triggers so it should work. It would be a different story if the trigger was larger though.