A few thoughts. One of the problems may be the size of angel you have been choosing as smaller angels and juveniles are usually a lot more reef safe than large 5-7 inch specemins. Angels aquired at a smaller size may be easier to "train" not to eat corals. Angels in the wild dont eat corals but as reef pickers many will tend to sample them in home aquaria. Having a lot of natural food options for them to pick at through out the day will definately help. I feed a lot of nori and gel based foods served up in those feeding grids and this seems to allow the angels to pick at their food instead of sampling corals. More frequent, smaller feedings also seem to help. If you have a lot of older, established live rock this may help as well as it also affords some natural feeding opportunities. Of the corals you mentioned the LPS are the most at risk along with zoo's and clams. HTH