All three are very good players mate. Jelavic was the most technically gifted of the three imo. Pršo arguably the most intelligent in terms of self management on the pitch, but when Morelos was on it especially in Europe two seasons ago could either Dado or Nikica lay claim to occupying good/very good defences single handedly? I would argue not to the same extent as Morelos.
However, Morelos has shortcomings in his game which are very evident when he is lacking in form and especially concentration, i.e. his touch. When he gets that back and starts scoring regularly again, I believe he will earn his place in the HoF (assuming he isn’t poached by some other outfit or tries to work his ticket again).
Those two assumption provisos come with a big IF prefacing them btw.