They used fingerprint analysis to establish prints on the medicine bottles found in the room. With the exception of an index finger print (Dr. Murray) on a propofol bottle and a thumb print (Elissa Fleak) on a syringe, the lawyers (prosecution & defense) stipulated that fingerprint evidence was inconclusive for anyone else. This could mean overlapping prints, partial prints, smudged/dragged prints, ghost prints etc....where LAPD could not identify an exact match. The report established that everyone present at the time of the incident had fingerprints within the house, but those prints could not be isolated.
Now as far as Michael being fingerprinted for identification, unless his body was unrecognizable to the family (say a burn victim) then forensics they would resort to fingerprinting or dental records and as a last resort DNA sampling(swab from inside the cheek or hair sample).
...Because Michael already had fingerprints on file (his arrest in Santa Barbara County), his prints would have already been in the police database, therefore forensics could verify them if it was requested. Since a visual ID was given by family, they most likely did not cross check the prints.
The million dollar question to ask however is, the blood drawn at UCLA from the deceased---was it Michaels?
The toxicologist was NOT the individual who drew the blood--->he was given the vials to analyze from Elissa Fleak and he never cross referenced them with the hospital id's. It has been established that Fleak has made a questionable number of mistakes in this investigation.
So you have to wonder....was it Michael's blood or not?