Based on a post on another thread, I asked a friend of mine who is a firefighter/EMT if CPR could account for the injuries to the ribs. This was his response:
"in my experience, every incident involving EFFECTIVE CPR has resulted in fractured ribs. the reson is that the ribs are connected to the sternum by cartilage, but the depth of compression necessary for effective CPR in an adult is 1 1/2 to 2 inches, which causes the cartilage to give way, resulting in fractured ribs (since the cartilagenous material is part of the rib)."
Of course, that still wouldn't explain the other injuries, but I thought this would be useful information to have.