I went and did some research on the Angels from the list since there seems to be some confusion as to their inclusion/exclusion from the USL. Here's what I found:
Centropyge boylei boyle's- Can't find any diet information and I've never even heard of one of these, much less seen one.
C. multifasciatus multi-barred- Eats algae, coral, sponge and tunicates.
Apolemichthys arcuatus bandit- After I figured out that the genus was wrong on this one, information was much easier to find! Sponge and tunicates compose 91% of this fishes diets (according to Fish Base. Notice how I give a specific statistic and then back it up with a reference???
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Holacanthus tricolor rock beauty- 98.2% of diet composed of sponges and tunicates. Again, from fish base.
Pygoplites diacanthus regal- Feeds on algae, tunicates, and sponges. I tend to agree here with Jeremy. The ones that come from countries where proper collection and handling techniques are utilized do quite well (like from Red Sea or Fiji). I have a Fiji regal here that I've had for almost 4 months. Fat as a pig.
Since many of these angels are sponge eaters, the question must be posed as to whether or not there are currently commercial sponge diets on the market. Anyone?