This explanation is consistent with what we know so far, except why were her purse, the cup of tea and an unfinished granola bar in the kitchen? She could have left the food on the counter before she took the kids to school, but what about her purse? Did she go inside, taking the purse with her, hear something, open the door to investigate, and was ambushed as soon as she did so?
The only problem with that theory is that, given the danger she knew he posed to her, would she have gone into the garage if she heard a noise, or would she instead have immediately picked up the phone and called the police? Also, if he wanted Dulos wanted anyone to believe his ludicrous Gone Girl scenario, why did he leave her purse in the kitchen? Didn't he know the presence of the purse was going to set off all kinds of alarms?
Based on the clear evidence, the assault clearly took place in the garage. How does the location of her purse in the kitchen fit into this narrative? That question has been bugging me. It doesn't change the fact that Dulos is guilty, of course, but it does tell us something about how the attack went down. I just don't know what yet.