if my tank would be bigger, I´d keep them too.
They swim aaround like sharks so there wouldn´t be a problem because they are not often on the tankbottom.
But u have to feed more other kinds first, because they will get as much as can before the rays from the surface.
I´ve heard a few times that Linces didn´t even eat feeder fish, they prefered dead food.
So I´d no problem.
Everything could be a problem, even the parents could kill the pups ...
I had two lince cats with an 8" motoro and they chewed off the edges of the rays a lot,, i wouldn't recommend it unless the rays are considerably larger.
if you tied another tank into your system you could move pups with no problems or risk.... all the same water.... then there would be better controll for feeding the pups and no risk on the lince possible hurting them...