Oh im not at all trying to stop you from doing what ever. Im sure you may know more about saltys than me. Im mainly speaking from experience. If you can get a clown trigger that is a proven eater then I would snap it up. I dont think you should mix triggers unless you have the room. My main point is just that undulated triggers are very aggressive.
I put that link to sfw.com in there because it says that an undulated trigger should live alone, by itslef, with noting else.
I get them in at work sometime and I have quit trying to put them in with any other fish. they end up costing me too much money. They stay in a 10 gallon section of a 220gal system. They are voracious eaters. But most triggers are so this will at alot to the bioload. The people who buy them usually have a large aggressive set up. Large eels, wrasse, large tangs etc....