To me, Mascherano and Berardi have priority. In mind, that Dani Alves has already signed. When they both arrive, you can sell one of Asamoah, Hernanes, Sturaro or Pereyra. Depends on the price. Then the central midfield is covered with Pogba, Mandragora, Marchisio, Lemina, Khedira, Mascherano, Padoin, Berardi, Sturaro/Asamoah/Pereyra/Hernanes. That is enough quality.
If Morata leaves is basically up to Juventus. Outbid the rest and he stays, simple as that. Morata can grow further and Mandzukic is the ideal stand-in.
May Morata leave, and you want to win the CL, add Ibrahimovic to the team. I know it is very controversial but with Ibra in this team we become unstoppable.
Another option I really don't know yet, as forwards has to acclimate. And with a ambitious season this is tricky.
For defense we already have a lot of options. We can always add a promising youngster may the opportunity arise but keep in mind we already have Rugani. The back positions are covered for a couple of years.
Dani Alves, Mascherano, Berardi, full ownership of Morata and (may the opportunity arise) some promising youngsters and I am satisfied !