I hope that you are right, Joe, and I look forward to seeing those pix in 6 mos., but I think that we would be more likely to see them if the water in the knights' tank was brackish.
The only possible way for them to survive long-term in FW conditions would be if we somehow bred the necessity of BW for osmoregulation out of them (as we have managed to breed Angels and Rams which do not suffer from alkalosis in alkaline pH conditions), but I do not see that happening without almost completely changing their genetic makeup.
pH lowering products have a tendency not to work because alkaline water has enough buffering capacity that pH lowering products will not make a difference until "crash levels." pH raising products need to be used in conjunction with buffers if the GH and KH of water is low in an area. Yes, they do not work singularly, but they do work with a little extra chemical work...which is anathema to most of us.
I would urge you to please consider putting the Knights in BW, but slowly acclimating them to it is necessary at this point. Also, you could ask the LFS from whence they came what conditions they need--but be prepared to take that with a grain of salt (which would hopefully find its way to your tank).
~Matthew
P.S. If I were truly following the tenets of PETA, I would not have any pets, and I would tell you to do so as well. Since I am obviously an aquarist, I cannot be called a PETA radical, nor can any of the rest of us.