It's tough, if not impossible to give a projection on these guys until we know who drafts them.
Drouin or MacKinnon have a lot better chance of succeeding early in Colorado with some other offensively gifted linemates than they would in Calgary.
You may want to update your sig to show the actual categories you use. "Yahoo Scoring" leaves it open to interpretation.
The way I see it, Mackinnon and Drouin could both be franchise cornerstones in their NHL careers. They are both prolific scorers but I would probably give a slight edge to Drouin after his 105-point season. Both are roughly the same size and play similar games although MacKinnon plays with a bit more of an edge. If you want to go based purely on stats to date, Drouin should edge out MacKinnon, but my gut tells me MacKinnon will be the better player overall. It will really come down to the situation.
I don't know as much about Jones, but his stats and the hype seem to have him right up there with these guys. From a fantasy perspective though, scoring d-men take much longer to develop than forwards. Looking back through D-men who were drafted in the Top 10, you have to go back to 2008 to find any that are significant fantasy producers (Doughty, Pietrangelo). Fowler and Hamilton are the only others who have made any real impact.
In conclusion, toss a coin on MacKinnon or Drouin for 1 and 2 over the next 3 years. They could produce anywhere from 40 - 70 points in that period depending on their situations. Hell, they could post nothing next year if they end up on a team that doesn't want to rush them (ala Huberdeau in FLA). Jones is a distant third for me as a fantasy option for the immediate future.