I don't fully dismiss them, but it is a very small sample size to measure a PP effectiveness.
I'll still dismiss calling him a PP specialist, at least if that is what you are projecting him to be at the NHL level. Look at the level of offensive talent it takes for a player to run a powerplay at the NHL level. I simply don't see him having that. He's closer to a guy like Dylan Larkin who can play on the powerplay, but he isn't someone you run your powerplay through. Young guys who come into the league who teams use as their powerplay QB are quite rare, and tend to destory junior or the NCAA to a much higher level. For example, McDavid, Marner, Drouin, Eichel, Huberdeau, Keller or Gaudreau. That's even if a team uses a forward in that role, as many also will run it through a defender like Karlsson, Josi and Klingberg. Look at the players who QB NHL powerplay 1st units, and I don't see Veleno having the talent to be that guy. I would think even the people who are high on him aren't expecting an elite NHL PP player. There are very limited spots to be that guy in the role he has success in at the QMJHL. Tons of players excel at things in juniors that have a limited chance of carrying over to the NHL.
No other ranking has him close to as high as you. No one else has him above 12 at the moment. McKenzie has him at 15, HockeyProspect.com has him at 20, with their head Quebec scout in extremely close proximity to Drummondville, and Button has him at 25. In my eyes, he's very similar to Mikey McLeod, who was a top 15 pick, and will probably carve out an NHL career.