I would certainly agree with Nicetry (no offense Sep), Nigers are far from docile as adults, they are great as Juvi's, but are quite aggressive as adults. This fish is recommended far too often on this site...It is not a good community fish as an adult. My first one tore a huge Maroon Clown to shreds after they had been together for 2 + years.
I also agree with RCreations, my Niger was far more aggressive than my Huma.
As for your tank Trigger Boy, you are rather borderline in a 75 with any Trigger, if you really want to keep one, get a small Blue Throat and surrond him with some moderate aggressive fish that can hold their own...Maroon Clown, maybe 6 line Wrasse, Coral Beauty Angel.
As to your Lunare ?...I would say no, this is a very large, very very very aggressive and territorial wrasse, I would not recommend this in that small of a tank