what characteristics do Ender and his launchie friends have which allows them to discover brand new Battleroom techniques?

In the battleroom, Ender learns by watching Bonzo and the soldiers. He studies the way Bonzo commands, learning both what to do and what to do differently. He also considers the formation of the toons, the subgroups of soldiers in the army (generally in groups of ten with one leader): the toons are too formal, too rehearsed, while more fluidity would give them an advantage.

That night, Ender goes back to his old Launchie barracks to get his younger friends to practice with him. He teaches them techniques from the armies and practices his new skills. Bonzo disapproves but technically can do nothing, so they come to an understanding in Ender's favor, but one that saves face for Bonzo before the other soldiers. All of them are quick learners.