I think Nikishin will have a very solid career, but I am not sold on him being a #1D. He may be, but I feel like the KHL is not as strong as it is perceived to be. He is not so young and has size advantage, but I think this advantage may be further mitigated in the NHL. I still expect him to be a good #3, maybe #2. I am also very open to the possibility that I am wrong and that he is better than I think.
Meanwhile, I think Demidov has star potential, since he did very impressive things at 19 yo. He has a lot of runway to transfer his KHL success to NHL success and then keep on growing. I also think he will fit perfectly with players like Hutson and Suzuki. I think that will amplify his impact.