The Four Great Commanders were determined, signaling that each person would lead a large army after the end of the Eagle Alliance's contest, collaborating with the power of the four dukes to start the conquest against the empire.
This was an opportunity for those outside of the Four Great Families to gain more benefits during the conquest of the empire, as cooperation with the Four Great Commanders was essential. Otherwise, the four dukes wouldn't have gone to great lengths to monopolize these top positions.
Deng Kong and Fan Wuyi were already from the Four Great Families. Unless absolutely necessary, no other noble seat wanted to simply follow behind the Great Families and settle for leftovers. To have a chance at the "meat," only Lu Hong and Qing Yuechu were contenders without significant backing.