I agree with Ron on the QT. Since you work at the store, just bring them home out of the suppliers bags.
Mysis is very good for tangs. Of course, they need their veggies, but meat will keep them fat, growing and happy. A well fed tang is a non-agressive tang. You should be feeding them enough to see them growing about 1-2" a year. They should be fat, colorful and graceful. Supplement their food with vitamins and fatty acids.
Anthias, wrasses and a lot of other true reef fish don't always do well with hypo salinity. Do your homework or you could kill them. This is another good reason to not do hypo in a display.
I have 2 purples, Powder Blue, Powder Blue x Goldrim Hybrid, Black, Hippo and Chocolate in my tank. Purple was first, then Chocolate and PBT. I guess that I am saying that a quality home (good reef-like water quality), lots of food and a healthy fish is more important than order. Too many people focus on order. Order might be important, but not as important as the other things (IME) and people overlook them b/c they are focused on order.