Zach, you seem to think Napoli is a bunch of mediocre players and Higuain singlehandedly took them to 2nd place. That's not the case. Sarri did a great job in creating a good team there, they will absolutely not fall apart after losing one player. A decent 15-20 goals striker is all they need.
Im not sugarcoating Roma situation, they need to sell only one player of the 2 because they aren't in as deep a $#@! as you think. Pjanic for 38M will be enough and then they will comfortably have their 40-50M mercato where they will keep their 2-3 most important loan players and get 1-2 good acquisitions for a low price. They won't have trouble maintaining their top 3 finish if Pjanic is their only significant loss. And yes, Radja was rumoured to leave but the latest he said suggests he will stay.
We seem to agree on Inter but Sassuolo, wtf. They lose their best player in Berardi and will sign some young players in return. Can't see them having the same kind of consistency as this season again. Best they can hope for is 7th place finish. Fiorentina will challenge for top 3, same as Milan and Inter, but I can see only Milan being a serious threat to Roma and Napoli IF they have a good mercato. They need a CB, 2 CMs and AM/winger depending on the formation. Maybe even one (or both) fullbacks. If they can get some good players and a coach they will be the most serious threat for a top3, but still won't be able to grab a CL spot in their 1st good season