I agree that if skeletal remains are recovered there is a good prospect of DNA recovery, and techniques have improved immensely since I was practicing in this field.Agree with opinion from articles read over many years not connected to this case. However the advance in technical forensics may be on William's side and 'our' side. It is absolutely amazing what current forensic technology is able to discover. IMO.
Any fraction of human skeletal remains may yield up a DNA sample and if it could possibly be matched to William's DNA or his biological family's DNA that may be a huge step in order to meet the standard required as 'proof of death' IMO. I understand that is precisely what the Coroner is required to make a decision on. Whether in fact William is deceased or alive according to the evidence she holds.
This below link will take you to the NSW Coroners' Court and on the landing page there are numerous links to very informative documents that explain procedures etc. The box with How the Coroners Court Works explains the processes involved in full.
Australia - Australia - William Tyrrell, 3, Kendall, Nsw, 12 Sept 2014 - #64
Linked copied to MS Media 'no discussion' thread page 7
I do have more than passing experience with the coronial system, and with coroners, but I have not practiced (in the forensic realm) for many years, which is why I won’t apply for expert verification.