I have a C. falcula, auriga, miliaris and semilarvatus in an 8' X 24" X 18" 180 tank. There is OCCASIONAL posturing between the butterflies (i.e. spine flaring and pretend nipping) but that is it. I don't know if your particular combination would work, but I have had no trouble. Also in this tank is a naso tang, Centropyge bicolor, bispinosus, and ferugata. I believe part of the reason they get along well (over one year now with each fish about 6 inches long) is that my live rock has MANY hiding spots and caves. The butterflies tend to shoal together most of the time, but they have places to go when tempers flare.
Bruce