I would take Celebrini over any of those guys without thinking about it, especially Bedard.
As a rookie Celebrini has a better PPG than all the guys you mentioned, and he's the youngest so I don't really understand how you can suggest the other 3 will be 100+ point guys but Celebrini won't, when he's already out producing them as a younger player and on the worst team in the league.
Also his 2 way game, the guys by far the best out of the guys you've mentioned. I've only see a couple Sharks games but for a rookie, the guy is great defensively.
Celebrini PPG .85
Bedard PPG .78
Michkov PPG .78
Demidov PPG .75 (KHL)
I'm not trying to be an ass, but I don't think you've ever actually seen Celebrini play because none of what you said makes sense.