Possible solution for Dragon Age Origins: Ultimate Edition DLC not appearing
For those who, like me, are having trouble getting the DLC to work in Ultimate Edition (downloaded through Origin), here is what I did to fix it. Hopefully it helps you too.
My problem was that the DLC had all downloaded and installed, but none of it was appearing in-game. The Other Campaigns menu item was grayed out, and the Additional Content menu was blank.
When my game installed, it installed all the DLC into the Program Files (x86)/Origin Games/Dragon Age folder where the game itself was housed. The location the DLC SHOULD be placed, however, is in the folder where the game houses its saves (for me, that is in the Documents/BioWare/Dragon Age folder). Both locations have an AddIns folder, but for me the Documents one was empty. That locations is where the DLC should actually be located. I copied all my files over from the Program Files (x86)/Origin Games/Dragon Age/addins to the Documents/BioWare/Dragon Age/AddIns folder.
Once that is done, there is an addIns.xml file that needs to be copied from Program Files (x86)/Origin Games/Dragon Age/__Installer to its equivalent in Documents/BioWare/Dragon Age/Settings. I replaced the Documents version with the __Installer version, and suddenly all of my DLC showed up in game.