I think if Horford and Durant sign, only minor adjustments will be made to the roster.
This season:
IT. Rozier. Jackson
Bradley. Smart. Hunter
Crowder. Brown
Durant. Olynyk. Bentil
Horford. Amir. Mickey. Iverson
Trade Jerebko/Young for a future 2nd.
Another option is if Horford agrees to a deal, trade Amir, Jerebko, Young, and two future 2nds in a sign and trade. Then sign Mahinmi or someone to be the backup center. Prefer to keep Amir and just sign Horford outright.
Next year:
IT Rozier. Jackson
Bradley. Smart.
Crowder. Brown
Durant. Yabusele. Bentil
Horford. Zizic.
That's 12. Add 2017 draft pick using Nets pick, best player available.
Can probably afford to re-sign Amir or Olynyk but not both.
Choose between Iverson or Mickey for backup center.
Hunter gone.