Previously in the linked article by you there was information that AMD is supposedly readying Vega GPU for Mac Pro, and that is supposed to go around may 2017.I'm inclined to believe it will be a dual Polaris really.
Stacc, indeed the info there is not very reliable since they seem to only copy and paste from somewhere else and add some extra sauce, most of the times with no sense at all. But the rumors are coming to this.
Where did you read about the GPU for the nMP expected by May?
Later, they have edited the article and cut out whole part about MP.