The problem with fishes is not all of them are consistent with their feeding habits.
Take tangs for example. Ang general consensus sa kanila totally reef-safe, pero I know friends that sold or gave away their tangs because the little demons nip at or even decimate clove polyps, GSPs or imported zoas.
I don't have any experience with butterflies except for the yellow longnose and Copperband. One thing is for sure though, even if they have been generally coral-friendly (even for several years already) they may suddenly eat corals if they are starving.
They are constant grazers like tangs and angels, if they are not fed frequently, they will find other things to munch on. So if you are willing to risk it, maybe training it to eat pellets first then feed it several times a day could help.
PS apparently some forums and online articles (like this:
http://orphek.com/butterflyfish-compati ... th-corals/ ) say latticed butterflies primarily eat octocorallians and anemones and just sample stony corals. If you don't have any anemones or octocorals maybe you could make it work.