yes you can have them all in your tank but thats not advisable as tangs produce lots of waste and will get territorial once they are stable in the tank........ BTW IMO one tang to me in a 4 feet tank is enough(looking at them when they poo, is crazy)..... Anyway my prediction is that after sometime, the fiercest tang in your tank will the white cheek and also that not a easy fish to keep. It has poor survival record, and get ich easily