Evander was never a HW but he is one of the baddest men to ever walk the face of the Earth. Too undersized to be a true HW.
I think Holyfield in his prime form could go all the way and unify in today's division. It's pretty dire.
His stamina and workrate alone would be too much for most including AJ and Wilder, Fury could potentially be a tough fight but Evander beats the rest fairly comfortably.