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).
I agree, Bologna played great last season and they have a chance to beat Napoli and considering Napoli (even with Conte) failed to make the transfers they want this summer, they look not that great. Milan, Inter, Fiorentina, Roma, Juventus all look like they could win. Obviously when you are betting on parlay like that, you take the risk that you may not end up with a win, you could end up with a loss and that is why I think it could be something difficult to handle, you need to make sure that you know what you are doing when betting on a parlay.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).
I would say a small amount, something like 10-20 dollars on this bet but with omitting Napoli, would be fine. It would both allow you to do better because Napoli is to risky, but also if you end up losing then this isn't a lot of money and wouldn't really hurt you neither. It would allow you to do much better and should not be an issue at all. It's the most important part, not caring when you lose in the end.