Not sure about dlc release or content,but 99% sure that the casino reference is because its your target at Crystal Palace (steal a list of customers if my aging memory is not failing).
Yeah I know. But it's pretty obvious with the collision physics that were present even in December that this was a place that you could visit.
Maybe there's going to be a soft rework in that specific ending where you go in this grand journey to help Mr Blue Eyes and enter to casino to do mission for him, and then followed up with Crystal Palace heist, something new and interesting happens and that's another entire new story that opens up.
Potentially other different endings like going with Panam with the tank you're going to get a totally different area unlocked and they have their own struggles that you can solve, perhaps you get to be a part of a bigger military that goes into corporate war... and other "ending" with Johnny taking over your body and leaving on a bus, maybe you get to go to Las Vegas and start a new life as a rocker boy. Things don't however go as smoothy and something happens.
I would hope this could be one way they could expand the game, rather than being linear experience, you're getting pumped with a lot of these DLC expansions to each new ending. Perhaps even offering entirely new lifepaths (which I've speculated in some earlier topic) where you could meet lets say Law officer and end up in Trauma team or NCPD, doing missions there and then cracking down the corruption in far more detailed story in the end while some paths with the original story would collide.