With a hippo tang / kole tang your options are pretty open, in my view.... these two tend to be ok aggression (at least compared to the "bad boy" tangs). I would steer clear of sohal / naso tangs, or others that get huge. Suggestions: Yellow tang / purple tang / powder blue (if you are confident in your fish keeping abilities).
Other suggestions - well I wouldn't have a tank, pesonally, without and angel - and the most obvious choice for me would be a navarchus - but you mention you have LPS, so it depends on what types you have and how valuable they are to you..... so maybe its not the best recomemndation
Pink tail trigger might be nice..... but again, shrimps etc are at risk.... maybe a blue jaw / blue chin, or even a pair? Again, maybe not the best recommendation
Anthias - great fish! Personally, I would go for the lyretail, and I would go for 8 females. I bought 6 a few months back, 1 male / 5 females. 1 female didn't make it through q-tine so 5 went into the display........ I was quite curious though, because 1 female was a bit bigger than the male, and I thought it was the strongest fish that would assume dominance and be "the male".... about a month ago, teh biggest female turned into a male! The only reason I can think this happened is that the female adapted to captive life a bit better than the male, she ate more food, and grew bigger....... hence my recomendation to anyone getting lyretails is to get all females and let the strongest fish change and assume dominance.
Other recomendations - the mimic tang was suggested - I would be cautious adding a red stripe mimic for fear the coral beauty mistakes him for a red stripe (Eilbs) angel..... but there are other mimics...... however I had a mustard tang (mimic) in a 180 with a regal (hippo) tang and they did not get along very well I'm afraid..... but you run that risk mixing any tangs anyway.....
How about hawkfish?
There are lots of fish to choose from really.......... did you have anything in particular in mind?