With regards to the blue/green chromis; be prepared that one or even a few disappear for no reason at all. Whether it be to poor health, predators, or infighting. People start off with a school and over time; they just seem to diminish in numbers.
An alternative to consider are Threadfin or Blue Eyed Cardinals. They also tend to disappear per se but less so in my experience. I'm not sure if that even made sense.
Also; as an aside - I'm partial to Triggerfish in the the Xanthichthys genus. Not as aggressive.
That's my 2 cents. Good luck.