I wouldn't recommend buying any fish with a good possibility you have to take them out later. This causes a lot of stress on your tank and is a real pain. I did this previously and my fish never trusted me again, running and hiding everytime I came up to the tank rather than coming out for food. Fish traps will sometimes work, but there is no guarantee.
If you want angels that do not nip at corals, look at the group called Genicanthus. Here is a link to some of them:
http://www.wetwebmedia.com/marine/fi...s/genicanthus/
You could probably look to get a pair of one of these fish instead of the 3 dwarf's and the bioload would be similar.