Why did you ask for advice if you didn't really want any? You had your mind made up before you posted. You've had some very knowledgeable folks chiming in and they are all telling you the same thing. Doesn't that kind of clue you in? No, you choose to listen to the two posters saying what you want to attempt is ok. These same people mind you, have a hippo tang in a 2.5 gallon tank. So take what of it you will:
Your tank is too small for the following: naso tang, hippo tang, clown tang, sohal tang, sailfin tang, powder brown tang, powder blue tang, atlantic blue tang, orange shoulder...
The ones that I suggest for your CURRENT SETUP: yellow and chevron/kole. OR purple and chevron/kole.
But NOT 3 yellows with some others. That's irresponsible reefkeeping in a 90. Whether you upgrade next week or next year doesn't matter. You should stock your CURRENT tank with the fish's FULL GROWN SIZE in mind, not their current size. And by the way, a 4" tang is not small. Not by a long shot.
If you add 3 or 4 to this newly setup tank, you're doomed. Not trying to be mean, just telling it like it is. As others have said, I've down this road and learned the hard way. Just because you pay for them, doesn't mean you should do whatever you feel like with them. And a 90 gallon tank is a 90 gallon tank. Open rock work doesn't give them any more room for swimming. They still can only go 45" back and forth. Less rock also means less grazing area. And you better keep that water pristine with tangs in it.
To all the folks here that said 'tang police this' and 'tang police that', it has nothing to do with that. We're simply telling this person the CORRECT way to go about stocking his tank to avoid him killing fish/getting frustrated with his unsuccessful tank.