I lost the first one in the first couple of weeks.... it's been almost 3 months with the female. She is getting fatter every day.... I see no need to pull her out ASAP, as you say. The male was exhibiting strange flashing behaviour at the very beginning that may have attributed to his death. I'm kind of wishing I had of treated him just to rule out health issues.
As said, I'm not having any problems with the second one. She is filling out quite nicely. There's another person on here that just pulled there's from their reef because it was not thriving in that environment. Why would I remove a fish that is doing well in QT? I feel it is more advantageous to train her very well on prepared foods, fatten her up to top condition, and then release her to compete with the other fish. I would never have been able to feed her the way I have, if I had her in a display tank. If I see her failing, I will change my course, that's a part of trying to "figure out" a difficult fish. But no one can say I'm failing, ATM.
The tank isn't as sterile as the pic you "quoted". That's a single coral skeleton I was using for training purposes. The LR in the tank has been set up for well over a year.
I am definitely open to suggestions, but you'll have to fill me in on the logic of pulling a thriving female due to a males death some 10 weeks ago. If the suggestion was given around that time... I could have understood it. I however fail to see how that is advantageous at this point.