The "Big Three Guys" ... no one among them had the bravery to get the Throne, they preferred to leave Tutankhaten - Tutankhamen become Horo. Even if the real power was in the hands of the regency council composed by Ay, Horemheb and Maya, the Horo was Tut.
The killer [if Nefertiti was KV35YL and she got killed] is among them [or at least the instigator of the homicide].
Plausible. I think it would be naive of us if we thought there were not all sorts of palace machinations going on. Tut may have been seen as the legitimate horo, but the power of rule may very well have been substantially in the hands of his top courtiers: this true of Amenophis III or Thutmosis III, but even moreso with a minor on the throne. I think that is born out by the later falling out between Ay and Horemheb. Once legitimate males heirs were no more, then someone needed to take the sceptre and marry the main heiress that was still around. First Ankhsenamun (Ay) and - just maybe - Mubenret (Horemheb).
To return a little to straight out plausibilities and a little away from purer speculations...
KV35YL. Who is she?
1. Nefertiti.
2. Meritaten.
3. Ankhsenamun (postulating that Ankhsenamun Tasherit was Tut’s Wife)
4. Beketaten.
5. Sitamun.
I think 3 and 5 the least likely, given time frames, but let’s keep the mind open here.
More importantly, what motives for her murder? Sitamun seems least likely (to me) to have been murdered.
Nefertiti as woman Pharaoh, I can imagine her removal.
One of them orderering a mail order Hittite Prince? That story seems so dubious to me. But the detail of the murdered prince gives me pause. Could that be the motivation for the murder? Ay married Ankhsenamun, but was Ankhsenamun still alive when he died? Horemheb had Mutbenret (???) Surely, if the story is true, Ankhsenamun, surviving Ay’s demise, must be the best candidate.
Still, there seems plenty of reasons why Nefertiti might be violently removed.