Je Tsongkhapa is known to be an emanation Manjushri, Avalokiteshvara and Vajrapani.
Does that mean Je Tsongkhapa contains the essence of these 3 Bodhisattvas? As people and myself have difficulty to think that Je Tsongkhapa is made out of three beings, enlightened beings. Can three beings be present in one human body?
You yourself are made of Your parents, and all of their parents, and so on... the whole 3600 million years of evolution down to the simple microscopic creatures called procaryotes. You do not exist without them, which means that they are all present in you and in your body. And also all of your earlier incarnations in the six realms of existence are in You, which makes even more beings than the ones included in the line of evolution on Plane Earth. These two lines of causation are in Buddhism understood to have produced You and Your biological entity, the body. You do not exist without them, they are in You.
"The form (ie Body) is never seen without the cause of form", Arya Nagarjuna.