I believe that GBC may have smothered her in bed. Remember the 000 call where he firstly mentioned "when we" went to bed, then changed it to I? Not a doctor, but am wondering if there is necessarily any blood when someone is smothered? If not, this may explain why there was no blood on the sheets. I believe he may have hit her in the head on something as he was trying to load her into the car. This may also have been the same time her tooth was chipped etc. If her head was hit, as has been mentioned in earlier threads, this may also account for the advanced state of decomposition in that area. IMO
I believe you are right in also stating that there are times when smothering does not cause any blood to leave the body. It is possible he hit her on the head but I am not sure where that occurred as no blood splatter had been found in the house, although there could have been splatter on the outside of the car and that has not been mentioned as yet. There could have been blood splatter in the carport that has not been mentioned so smothering in bed is a definite possibility.
I believe the major damage was around her jaw which was in contact with the muddy water. Allison's body was mummified on one side and severely decomposed on the other and her neck and chin on one side had completely deteriorated. They stated that they thought there was possible damage to her chin due to the way the decomposition had occurred. I didn't think there were any fractures on her body at all but I could have misread the report.
Just thoughts after reading so much in the last few days but there is so much detail to remember. I really don't know if I am even close in what I am imagining happened. Only G will ever know and I don't think he will ever tell. I am very curious to see what scenario the prosecution presents in determining how Allison ended up under the bridge.