regarding the blue-green chromis, yes. theyre completely chill, attractive fish. make sure that you get several(i had 7, and they schooled), and that the tank is peaceful overall.
as far as clownfish go, yes, theyre damsels. false percula clownfish arent aggressive by any means. however, there -are- aggressive clowns, so be weary.
either of these species are readily available from your lfs or online, and i think both are excellent choices. im certainly pleased with mine.