First order of business, we need a cash flow going. Selling Bacca would generate a tidy €30-35m for us to work with.
Antonelli and De Sciglio aren't cutting it at left back, so we need a new guy there. Adam Masina from Bologna would fit the bill, and would cost perhaps €10 million. This would be offset by the sale of De Sciglio to wherever, for something like €8m or whatever a club is crazy enough to pay us for his services.
Honda is honestly terrible. If we can get €3m for I'd be very surprised, but he also needs to be gone. This means that there is €31-36m to work with without going into the red.
A striker needs to be signed up, as Bacca is now gone. Leonardo Pavoletti seems a good choice, but he's only had a good season and a half in a top league in his whole career, which makes him a bit of a risk. Torino's Belotti is a possibility but again, the issue of risk arises. Belotti would be a safer pick up, as he is better suited to playing off of others + is younger.
Belotti, however, also had a decent 14/15 season with Palermo, which edges him out slightly. His price would almost certainly not €15 million, leaving €16-21m to spend. Assuming Bacca leaves for a price in the middle, it's €18m left.
What's left is getting a good defensive midfielder. Montolivo has shown that with proper protection he can be very good on the ball, but he is lacking that proper sort of partner at the moment. One of the youngsters could fill this role one day, but Milan needs something now. Dominik Kohr of Augsburg is exactly that type of midfield enforcer. He's tough and his 12 yellow cards show he's not afraid to challenge for the ball. He'd likely cost us the rest of the money as well.
FINAL VERDICT:
OUT: Bacca, De Sciglio, Honda
IN: Andrea Belotti, Dominik Kohr, Adam Masina