DWD Theory Execution
Both Oregon and Washington passed "Physician-Assisted Suicide" before Michael's 'death', the state of Oregon on November 8, 1994; Washington state on November 4, 2008. For both states, the DWD patient must have 6 or less months to live. (http://euthanasia.procon.org/view.resource.php?resourceID=000132)
Here's where my theory comes in.
Hypothetically speaking, let's say Michael found a DWD patient who agreed to die in place of him on June 25, 2009. This patient would have had 6 months or so left in his life. Remember this National Enquirer cover dated January 12, 2009:

If you recall, the months leading up to June 25, Michael was seen more in wheelchairs and visited Arnie Klein frequently- perhaps to pretend he was sick. Who knows who truly released the information that Michael had 6 months left to live? It could've been the mastermind himself. If Michael did use a DWD patient to hoax his death, that would explain why he would "have" that many months to live, because it was required by law!
I think leading up to June 25, the DWD patient underwent plastic surgeries to look more like Michael (explaining Michael's frequent visits to Arnie Klein), and doctor visits.
Fast forward to June 24, 2009. In LaToya's book Starting Over, she states that " According to fans, when Michael was on his way to rehearsal on [June 24] the day of his death, as he drove through the gate at Carolwood, he did not roll his window down and talk to them. That was totally out of character for Michael. I've never known Michael to behave in that way to a group of fans that had been so devoted to him [...] Then, when he arrived at the Staples Center, he didn't walk over to his fans[....]. Michael may not have rolled down his windows because the DWD patient, who at this time was supposed to resemble Michael, was inside the car with him.
LaToya also says that "[...] on the night of June 24, 2009, the last night before he passed, when he arrived home from rehearsal, the security measures at the house were much different from any other night when Michael returned from rehearsal." <--To prevent anyone from seeing the patient?
"A line of roughly ten men were lined up on both sides of his gate. Normally, he had only the two or three security guards that were with him, and the one that was in the post inside the yard. But this night was different, security was everywhere, and again Michael's car didn't stop on the way inside the gate [...] [One fan reported:] 'I stand outside the gate, and Michael has the same routine every night. After he comes home from rehearsal, he goes upstairs, and about twenty minutes later the light in a room goes off. The night that he died, the light stayed on all night. I got worried. The light never went off. I didn't get it. I didn't understand what had happened. It was very strange [...] Oh, and security was acting strange,' she said" (326-331).
All of the excerpts of Starting Over can be found on http://www.michaeljacksonhoaxforum.com/forum/index.php?topic=19778.0
Once again Michael did not greet the fans. The light may have stayed on the entire night because Michael and Conrad were preparing the assisted suicide. Could also explain why Conrad performed CPR on the bed- he didn't really want to save the patient, because he was supposed to die.
I think that the DWD patient died that day and that the autopsy was performed on that patient, with some of the information added by Michael to make it appear authentic (i.e. the vitiligo).
http://www.hlntv.com/slideshow/2011/11/01/michael-jackson-autopsy-file
Scars from a surgery: Depending on what the DWD patient's ailment was, these scars may have been from the surgery.
http://cnninsession.files.wordpress.com/2011/11/jackson-autopsy_short-copy.pdf
"The head is normocephalic and is partly covered by black hair. There is frontal balding and the hair can be described as short and rightly curled." (12). <-- Maybe the DWD patient had chemotherapy.
Well, that's all I have on the DWD theory for now. I hope everyone has a Merry Christmas! :)