Buium will be a mystery for awhile, playing in college. Yakemchuk, Parekh, and Dickenson played NHL exhibition games. I assume Silayev and Levshunov will play NHL and/or AHL at some point this season, so we'll get a good look at them too against pros. And Silayev of course played KHL.
I liked Buium and what I read about pre-draft, although being a LHD, I wasn't nearly as interested as the RHD. His biggest obstacle to becoming a star 2-way defender could be that he's a little guy for a defenseman, although certainly not tiny. Although other smallish d-men have been outstanding players. Will he ever be strong enough to handle opponents in front of the net and along the boards?
Buium's 6 feet. His height isn't going to be an impediment to becoming a great player and if you're worrying about the weight and strength of an 18 year old then you're worrying about the wrong things.