If the main acts were to be played by both Sheng Li and Wan Yi, with Bones and Freya unveiling the curtain of the stage and Claudia and Keeno controlling the lighting, then Jon and Ally were positioned right in the back, exchanging the props and setting up the stage.
Each of the individual forces has its role to play in the daring plan of Wan Yi's. He and a few of the elite forces are going ahead to face off against Sheng Li right as he is setting up his main camp, while Freya and Bones are to cast a wide net over the entire area, preventing anyone else from knowing the exacts of Wan Yi's plan and accidentally running into a head-to-head battle against two of the hornier Heavenly Lords.
To be honest, Wan Yi could have totally brought Jon and Ally along, but if he did, then in the case of total failure of his plans, they would have lost the base also.
