I thought yellows were one that you could do 2-3 if you added them together? I could have sworn I've seen multiple tanks with 2-3 yellows but maybe I'm just having a brain fart moment.
As far as nutrient export, I think ours is pretty strong for our tank. Lots of CuC, skimmer rated much higher than our tank, biopellet reactor, and some other stuff. Not sure how much more I could add to control nutrients (other than me making sure I don't over feed of course haha).
Edit.. for nutrient control you're talking about having 2-3 zebrasoma tangs, the PBT and our current line up I think? I think we have a pretty good setup for that and can/will add some other additions down the road (like algae scrubber, we're already plumbed for one, UV sterilizer, etc).
So if I'm understanding you right, you're saying 1 zebrasoma (yellow, sailfin, etc), 1 tang of different family, and 1 more of a different family. Sorry for blowing you up with tons of questions.