I've heard no teaching about this explicit question, so I can just answer it from my point of view, or my perception.
Avalokiteshvara, Manjushri and Vajrapani are no firmly attached solid beings like human beings, but they are aspects of the Buddhanature or Buddhamind.
Through the aspect of Avalokiteshvara there is Compassion, by the aspect of Manjushri there is wisdom and by the aspect of Vajrapani there is strong power.
So, having realized these three, Tsongkhapa brings Compassion, Wisdom and Strength to the human beings who meditate this.
So they also can realize these aspects and in the end they are also emanations of these three - at the end there is no "They & I" but just one buddhanature, one dharma.
Because, if our mothers, who have been kind to us
From beginningless time, are suffering,
What can we do with (just) our own happiness?
From 10th of 37 Bodhisattva Practices