They generally don't mess with much. Their smaller mouths don't do a ton of damage, even to inverts they do go after. Had my Hawaiian Blue Spot with snails and while it did pick at them, it was never enough to kill them. He did manage to rip a claw off a CBS, but afterward left the shrimp completely alone. I wouldn't risk putting a cleaner shrimp or peppermint in with one though, or soft-bodies inverts like a lettuce nudibranch or a Sea Hare. However my Blue Tuxedo urchin and Cowrie were not touched.
Very few saltwater fish have those "long flowing fins" the place you read that info talked about. Long flowing fins generally means poor swimming ability. Off the top of my head, I only come up with Batfish and Lionfish. I wouldn't mix Toby puffers with either.
Mine did nip at some corals. GSP, Xenia, and for some random reason one day nipped all the new buds off my Bali Green Slimer. He never did it again though. But he did munch on GSP, and shared duty with my Blueface Angel removing any traces of Xenia from the tank.
If your coral plans are mostly LPS, larger softy corals (toadstools, kenya trees, all types of mushrooms/rics, etc), or SPS, they should be completely fine. If you really want a tank full of hermit crabs, probably won't work, but they won't wipe the population completely clean, or even dent it in one night. You could just replenish as needed.
