I also think you should stay away from the damsels. Eventually you'll want to add some other smaller fish and the damsels will destroy them. If the five yellow tangs are the only tangs in the tank and you don't add much more for bigger fish than I would say go for it. Add them all at once and there is a possibility you won't ever see aggression issues.
Actually, last time my tank was up I had a wide variety of fish.... This time im thinkin Tangs, Damsels, and afew Anthias. Then all out coral. Perhaps I'm more of a devil than the Blue Devils. My biggest concern is that five Tangs will result in high nitrates and brown sps.
If the damsels fight, oh well... Thats kinda nature. If the Tangs fight, I will catch them and give them away... Hopefully in time. If my Anthias get killed by damsels... Errrrh.
Im a gambler, but if enough oof yall with more experience than me say that its gonna be a blood bath... I wont try it.