The dining car staff should keep any remaining main menu items for the sleeping car passengers, though the selection might be less and less diverse until the stock is depleted at which point the "emergency rations" would be given to sleeper pax. Coach passengers will be offered the "emergency rations" and will likely not have the option of regular menu items, though this call is up to the LSA (all depends on if he/she can feed all the sleeper pax and still have stock left over,) and the regular menu would be charged at the listed rates where-as the stew-over-rice would be free of charge.
Additionally, the "service recovery packs" of crackers and/or chips might be offered from the cafe car. It all depends on if the train gets any later, how full the train is, etc. As for passengers who have connecting trains in Chicago, Amtrak Customer Relations staff should be getting on at an earlier stop to begin arranging accommodations for those who will miss their next leg. Once the train pulls into Chicago, all affected passengers will then be directed to the Customer Relations desk where hotel arrangements/food vouchers/cash for cab service should be issued. Additionally, reservations for the earliest available accommodations on transportation to the passenger's destination should be finalized at that point.