hi.... Basically for angel is a try of luck... hit miss.. like i say be4, i nv had any encounter of angels wacking corals, but had a few encounter of tangs tearing my corals apart so now i rate angels more reef safe than tangs...
venustus angel is the only reef safe dwarf angel(another is resplendent but that one reef safe because it is captive bred) in the centropyge family.... so that one i have no worry
I heard many terrible story abt singapore angel, so i wun try that.... quite a few report on lemon peel nipping stuffs, but since mine is a hybrid, behavior may be different....
IMO flame angel is a hit or miss.. It is either very terrible or very reef safe.. lucky ppl get flame that dun touch anything.. unlucky ones(most of the case i heard in RC) get their coral tear apart