Swap Savoie to the bottom and that's how I'd rank them, Nazar, Gauthier, Kasper, Savoie.
I've read a little more into Savoie and I don't know if I like him more than those other 3, but he's still a top 15 pick in my book. People smarter than me question his sense, which makes you question how high you want to draft him. However, he is a case of sense does not equal vision as his vision for passing is very good. Basically he's best when his team already has possession in the o-zone and creating plays there, he's not going to be driving transitions at an above average rate.
Kasper appeals to me as the safe pick, he'll be a solid 2-way second line center in the NHL with good speed and physicality. I don't think he'll put up crazy points but he could carve out a Jordan Staal type of career where he pots 40 a year mostly just due to tilting the ice his teams way and playing effective hockey. Effectiveness is the name of his game, doing what it takes to help his team win. I think Gauthier brings similar things with more goal scoring though which puts him slightly above Kasper in my opinion.
And then you've got Nazar who I flip flop on, but his ceiling is high. He's a manipulative and speedy little guy. Unlike Savoie he will be a one man transition for you while also bringing the high end offensive abilities. The reason I flip flop on him is because in the spot our team is in a guy like Gauthier or Kasper who you can confidently project as a center and stabilizes the middle 6 long term is so attractive, and we've got Raymond who brings that game but better and Berggren who may be good enough to do it at a 2nd line rate.