Markieff Morris, Tobias Harris, Danillo Gallinari
They each slot in to the "swing" position in CBS system. None are true bigs. None are true wings. They each add more scoring, but all of them could really play next to Crowder (our second best player) because of Crowder's and their versatility.
Morris is the best contract and can probably be gotten cheapest.
Harris is the youngest with the most upside.
Gallinari is the most proven and probably the best shooter (in a more shooter-friendly system).