If you want a yellow tang, get one. You could always remove it if a problem arises. There are hundreds of reefers who have kept multiple tangs in a 125.
She knows she "can" get one. She is asking if she should. That is known as practicing good husbandry. I don't know about Fishmommy, but I would never want to add a fish that I had to worry about catching again.
While the odds for success (anecdotally) favor tanks where the CBB was added first, there are still numerous reports of a yellow tang not coexisting with a CBB. Also, in a minimalist aquascaping, there are likely less places for the weaker fish to hide.