55 Gallon Saltwater...Any ideas?

no, you cant go tang crazy like that. especially if youre going to cram them in a small tank. tangs are aggressive and they're going to fight each other. especially when they are put into a tank WAY smaller than their minimum needed size. i would skip all 3 tangs altogether. invertabrates, fine, go for it. shrimp are great. i would do the clown fish in a pair. another idea is to go for dwarf angels. i see that you like color in your fish, try a flame angel, they look great (you wont be able to have corals though) good luck.