Only piece of advise I would give is add them at the same time. I added my black,yellow, and chevron all at the same time into my 265. with no issues. On a side note it's funny when you say only a 200 gallon . Years ago that would have been a monster of a tank!
Does anyone understand why it is advantageous for these tangs to mimic angelfish?
I seems to me that from everyone's experiences (and my own) that they are somewhat delicate when it comes to changing tanks. Do you agree?
My friend recently gave me one that he'd had for several years (full adult colors and was beautiful) but it didn't last a week in my tank. It's pretty odd since all my other fish are doing fine and all the water tests indicate great parameters. He looked sickly from the moment we got him into the tank.
Maybe they don't respond well to change?