The info in the app gets more complete/accurate as you get closer to sailing. While Q class ships have four named main dining venues, for the app it is just considered the MDR - the menu is the same in all of them as well as under the MTD listing.
There are two versions of Ripcord and Northstar - usually, you can only book the free version on board at certain times, the paid version should become available in the planner closer to sailing.
As mentioned above, use the online web browser based planner for purchases pre-cruise. For more complete/accurate general info, set the app to the current sailing, not yours.