It's too hard to tell, as youngsters change rankings annually. But, based on what I've seen so far...
1. Hutson -- Elite, offensive defenseman in his prime. He will run a lethal PP on the Habs and score between 70-90 points a season... 95 in a top year. Even as a pup, he looks like a young Phil Housley or Erik Karlsson out there. He's an amazing talent who can snap a game wide open.
2. Cooley -- A silky smooth talent. I don't feel Cooley will end up contending for an Art Ross but he'll be very, very good like Sebastian Aho. I believe he will be more valuable than his points suggests and will soon be the best player on the Yeti.
3. Slafkovsky -- He could emerge as the best player on the list when he puts everything together, based on his skill and size. That said, I wouldn't bet on it. Although I don't see Slaf becoming a superstar, he should end up a very important player for a promising Canadiens club, producing between 65-80 points a year in his prime. Within 2 years he could be a 35-40-75 threat playing with Demidov, Hutson, Suzuki, Caufield, and crew.