First of all, your Reinhart's numbers are really off, since Reinhart only played 9 games in his Draft Year+1, and Galchenyuk had 27 points in 48 games in his Draft Year +1. You started with their Draft Year +2.
Second, here's their production per 60 minutes:
Draft Year +1
Galchenyuk - 2.74
Reinhart - 0.64
Draft Year +2
Gakchenyuk - 1.99
Reinhart - 1.89
Draft Year +3
Galchenyuk - 2.1
Reinhart - 2.07
Draft Year +4
Galchenyuk - 2.52
Reinhart - 2.14
Reinhart gets more points, but he plays more than Galchenyuk.
For the record, I grade Reinhart as more valuable because of his even strength play, but don't expect Canadiens fans to consider Reinhart either a better fit for the Canadiens or more valuable in a trade. I get why Buffalo values him more and from their POV I agree.
And the gap between them is more than negated by the difference between Pacioretty and Okposo.