To answer the question the yellow and a kole will get along, FME. Adding a flame and clown shouldn't be a problem either. I dont know how aggressive maroons get, but heard they can get quit nasty. Don't know anything about scopus tangs.
That said, your tank is not really big enough for 2 tangs. If you had to have 1, maybe the kole only, but check out what others say on minimum tank size.