Yes, the scouts' job is to pick players who become NHLers.
I don't think that's the expectation, but it is the intent.
There isn't really a formula to drafting. You're almost always going to let them develop under some other coaching staff for at least another year. Personality doesn't entirely matter, nor is it physical gifts. You need a mixture of both, and one, or both, may not be apparent at the time of the combine. Immature players can mature, but a 'mature' 18-year-old can also stay that way.
We talk about late picks, and Tom Brady was one, but people still make fun of his combine picture. Sam Bennett, a very high pick, couldn't do a single pull-up at the 2014 combine. Henrik Lundqvist, a late pick, was doubted by some because he was too good-looking to also be a great hockey player. (also what held me back, btw)
If we picked more analytical and internet scouting darlings, the perception (and expectations) of our prospect pool would be much higher.