I have an imperator juvi in my 75g right now. He's only in there temporarily until I finish setting up my 150g. Hopefully by this coming weekend, he will have twice as much room to live in. He has been in the 75g for about a month, and has done pretty well.
He is growing fast though, so for you, I would not recommend either of the angels mentioned due to the size of your tank. However, to answer your question, Brain corals, Acans, Trumpets, and and Zoas would be toast in short order. My tank is dominated with SPS corals, and I also have a few LPS tentical type corals as well (Torch, Pearl Bubble, & an Ellegance). I HAD a few zoa colonies as well, but they were eaten within the first week. Since then, he has not messed with anything else, and is relatively mild mannered towards the other fish. (Yellow Tang, Watchman Goby, Firefish, and a couple Cardinals) He is deffinetly the boss of the tank, but he doesn't beat on any other tankmates.
Again, I would steer clear of the large angels for your 75g tank. Maybe some of the smaller angels like a coral beauty, flame, or potters would be better suited for your setup.