The dwarf and pygmey angels are not a problem in that kind of tank. My potters angel is almost competely herbivorous but does eaten frozen meaty feeds. Likewise, a flame or coral beauty would do well. My tank is covered in sponges as well as the other things you named. The only thing I noticed was that the Christmas tree worms disappeared shortly after I introduced him. Other then that, I have not noticed him picking at anything in the tank and he has been in there for a year. There was a really good article in one of the fish magazines a while back about angels. There main conclusion is that angels are usually only a problem in reefs when they are not being fed enough. They will then go "live off the land" so to speak. This mainly applied to the large angels. The smaller angels are lot easier to keep in a reef and most reef keepers I know have, or have had, one in their tanks.

http://www.marinecenter.com/fish/ang.../pottersangel/