This franchise has no appeal in the west, the amount of people overestimating the success of this game is wayyy too high (10 million, really??).
The fact that this game is going to be released later on the PC will already make that platform irrelevant in terms of actual sales, a late release means that the hype for the game has died down and it will basically be ignored for the most part especially during a time where games like RDR2 and Anthem are going to release, it's almost impossible for this game to gain any sort of following on the PC, especially in the west.
The Xbox has never received Japanese games with open arms except for franchises like Dragon Ball and Naruto which are very popular anime franchises that have a very substantial western audience. So it's probably going to sell like a dud on the Xbox One.
The PS4 owners, for the most part, will buy the game but it will reach nowhere near the 5 million mark, the max it will do is 3 million (that's being generous) and a large chunk of that will be bought by the Japanese owners.
Final verdict:
PS4: 2.5 million
Xbox One: 0.7 million
PC: 0.1 million