Yes the Nem will sting your corals just be sure he gets enough light and a bit to eat The damsel may be hiding cause he's in a new place give him a few more days
What are your water parameters?
Leighton I think he/she is using a Translator to post, most do poorly with slang or miss spellings
Most people create their own problems by not following the basics and refusing to stock appropriate to their system. Gregcoyote 2013
SPS = Stability Promotes Success