I'd pick Halaand based on his age, but I won't give him a chance until he's leaving the Bundesliga. Werner and Chelsea flog Batshuyi were all stars in the Bundesliga, so I don't think they're serious.
You can gauge how good a player is, especially a striker, by how they play against other big European opponents in the UCL and Haaland has been promising.
Based on his style of play, I am very positive he can thrive in any league, so long as the midfielders feed him with the balls. The good thing is that he won't be in Dortmund for long. We shall judge thereafter.