The proper starting lineup would be Bradley - Green - Kuzma - James - Davis. That will give them the most optimal spacing on offense and the best chance to put out a decent defensive group.
Bradley and Green can provide enough defensive pressure at the point of attack, Davis can anchor the middle, and James and Kuzma can take the wings. James can run the point on offense, Davis can be the go-to scorer, and Kuzma, Green, and Bradley can space the defense.
Rondo, KCP, and Cousins are all far too poor of defensive players to start and don't offer nearly enough offense nor particularly complementary skills to Davis/James to deserve a starting spot.