why not do some different kinds
yellow tang
powder blue or brown
bristle tooth tang
that'd be my recommendation on a trio of tangs, relatively different looking to where they shouldn't fight and since these guys dont get too big they should be okay if your tank is has lots of swimming room I would avoid any other water column fish with this trio, I would stick to rock/perching fish (blennies, gobies, firefish, basslets) and thats all
my tang beat the snot out of a coral beauty because they were both trying to nibble on the same algae patch