No way on three tangs and an angel in this small tank! This is a single-tang tank, and may not hold any tang for life, much less three. Have you had the chance to check out the site I linked you to? Stocking should be a well-researched and thought-out process, and these combinations you're coming up with don't appear to be researched at all!
As I said before, count on having ONE centerpiece fish, as well as other smaller fishes. You're not just looking at swimming room, even though that's important, too -- you're looking at bioload and how psychologically crowded these potentially aggressive fish will be. Overstocking of the magnitude you suggest will only lead to trouble!