I have little doubt that Brown will start game 1, with Henderson next up and Akers 3rd. This isn't about ability; it's about knowing the system, the plays, the game itself, and reliability especially as a 3rd down blocking back.
Brown is a hammer, so he won't hit any home runs. But he rarely loses yards because he's a north-south, get your shoulders square and go type of back. McVay can use jet sweep action to get some runs from our WRs to add to it.
This will probably change in a couple of games or so, (depending on its success) but I predict that's how it'll look against Dallas.