Tutankhamun's mummy
On January 15, 2005, under the direction of Dr. Madeeha Khattab, the Dean of the School of Medicine at Cairo University, Tutankhamun was removed from the tomb and a CT scan (computerized tomography) was performed on the mummy. The scan allowed for accurate forensic reconstruction of his body and face, as well as further evidence of his cause of death. Testing showed there was no traumatic injury to the head, he had a small cleft palate that went probably unnoticed, and the elongated shape of his skull was within the normal range and appeared to be a family trait after some studies were done on mummies that were believed to have been related to Tutankhamun. Based on bone maturity and his wisdom teeth, Tutankhamun was confirmed to be 19 years old at the time of his death. The CT scan proved Tutankhamun was in good health and did not show any signs of disease that would have affected his build. Study concluded he was not murdered from traumatic head injury, but a non-violent murder could still not be ruled out. There appeared to be no indication of any long-term disease.
Smenkhkare
As shown on the box from Tutankhamun's tomb, Meritaten came to take Nefertiti's place as royal wife late in Akhenaten's reign. Marc Gabolde has proposed that Meritaten is "Dakhamunzu" and the dead king is Akhenaten, in a number of articles. He supposes that Zannanza completed the trip and died only after ascending the throne as Smenkhkare. It is after the death of Smenkhkare/Zannanza that Meritaten assumes power as Neferneferuaten.
Meritaten seems the least likely on the basis that at the time of Akhenaten's death she would only have been about 20 years old. By contrast, Ankhesenamun would have been about 25 and been queen consort for some 10 years. It seems unlikely that the young Meritaten would have the wiles to deceive Suppiluliuma, maintain her interregnum in the face of pressure to marry a 'servant' and conceal the presence of a male heir in the personage of Tutankhaten.