Found an interesting article regarding aspect ration and resolution for The Order 1886. From my understanding, rather the developers choose 800p, or 1080p, the game will still feature the black bars, aka letterbox, around the screen. If they choose standard 16:9 aspect ratio, rather it be 1080p or 800p, it would still be letterbox format, by the developers choice. The field of view would be more "closed in" and not have as wide of a viewing angle, as a 2.40:1 would. The developers are aiming for 2.40:1 aspect ratio. In other words, the letterbox format isn't going away no matter what aspect ratio, or resolution the game is rendered in.
As far as resolution goes, 1080p would mean no MSAA, which would mean more jaggies. Less jaggies = a more pleasing to look at. So I'm hoping for 800p 2.40:1 with 4xMSAA. Here is the article for anyone that might be interested. http://www.gearnuke.com/order-1886-169-vs-2401-aspect-ratio-one-better/