I share your view on Demidov, it will take time till he adjusts to the NHL game. No one can convince me that the KHL has anything near the rough stuff and speed of the NHL. I would put it somewhere between the AHL and NHL, and we have all seen the adjustments AHL players go through.
With all that said, he could hit the ground running and produce right away, which would be great, but it's better to shelter him as much as possible and see how it goes.
I don't think I would play him with Laine and Newhook, but Evans might be the safest starting point.