I think I'd take Elias Pettersson. I'd take Lias Andersson over both though.
Andersson is not nearly as talented as Elias Pettersson. Andersson is an amazing case of hard work beating talent which he has very little off. But hes not nearly as talented as Pettersson and is far more closer to his ceiling than Pettersson is seeing how he's more physically mature.
In my eyes though, i'm 100 percent sure Lias Andersson will be a NHL player to some degree.
OT: Very close poll, but i'm going to go with EP for his potential and him being a center. Very close though.