The long and short of it is yes, in a large enough tank. Usually nigers are fairly docile but there is always the exception. It is difficult to predict wether any trigger will or will not bother sedentary elasmobranchs but it is best to err on the side of caution.
I do have one question, though, what size tank are the shark and ray in presently? I don't want to make assumptions based on the little info listed for you. I would suggest that they most definitely need to kept in aquaria over 180 gallons or more. The banded shark can reach well over three feet in captivity and the blue-spotted ray over 18 inches.