We (they) put an angel in the FV softie tank, and they didn't have any more zoas after 2 weeks. No experience with a coral eating angel on lps/sps, but I would believe what you read on coral eating.
Edit; I looked them up and they are a pygmy angel, again, no experience with it directly, but I have a coral beauty which seems to not nip at corals if well fed. It does look more like a flame angel, which is known to be more nippy at corals.