I believe it happened as Junior said it happened. I'm not sure I believe the forensics in this case, or rather the investigators. JMO!
JB's attorney never disputed the forensics though. He did claim that the forensics could support several different people positioning scenarios, which while possible by the laws of physics were impractical considering the sequence of events according to JB. Its sort of like eliciting the answer: yes, its possible you can flip a penny 20 times and get 20 heads in a row. That was the nature of his questions to the ME and forensics experts.
To me, the 2 shots to each is huge. If there were one shot to AH and one shot to TH which was not in the back of the head...JB's story would hold more weight. As the pros pointed out, how could a struggle with a shotgun at close range cause a wound to the back of the head?