Compatibility question (tang and angel mostly)

[wiggie]

I currently have a FOWLR 75g setup with a clown, xmas wrasse, and a flame angelfish.

I am looking to purchase a few new fish, possibly a purple firefish and a green cromis. But not decided for sure yet when or even if. (i'm trying to get all the colors of the rainbow )
But my questions are that i'm looking to buy a hippo tang or yellow tang possibly both.
And now before i have EVERYONE freak out that those fish are too big for the setup i realize that full grown they would be but i would be getting them at only 1 inch big and am goign to be upgrading long before they would be too big for the setup and I have a sufficient protein skimmer for the bioload.
My question is that my flame angel is inbetween 2 and 3 inches and by everything i have researched he is the only fish that may have a problem with the tangs, and honestly if it just came down to getting rid of him and buying a smaller one at the same time as the tang(s) i would.
Any feedback would be extremely appreciated.