I doubt only Napoli here. The remaining ones are highly likely to win in my opinion. You would guess the reason why I doubt Napoli. They were beaten by Verona really hard last week...

They still don't seem ready for the new season honestly. There is still a striker problem to solve on one hand. They say Lukaku deal is close to happy ending but let's see.
The thing that might help them is that Bologna don't have Motta as their manager anymore. Vincenzo Italiano has taken over and couldn't make a good start (1-1 vs Udinese home).
You're not alone in doubting Napoli. Because I think almost all of us here also feel the same doubts about Napoli after they lost badly in the first week to Verona. But talking about their next opponent, namely Bologna, actually the Bologna club is also in quite the same situation. Because they are also currently adjusting to their new coach, Vicenzo Italiano. And actually Vicenzo Italiano is a coach who is quite reputable. Because when this coach trains Fiorentina we can see that Fiorentina has always been one of the clubs that competes strongly at the top of Serie A. So I think Bologna can also become a quite strong club under the coaching of Vicenzo Italiano. It's just that it will take time for the new coach and the players at Bologna to understand each other and adapt to the strategy created by the coach. And Napoli are also in the same situation with Conte. And yes, Napoli's current weakness is just waiting for their main striker to be able to appear on the field soon. And yes their target is Lukaku. Maybe that's when Napoli will return to better form when the Lukaku transfer is complete.