Guys I just bought the entire Sims Pack on steam with all the DLC available on Steam, Right click on the game in libreary and click "View Support Information" Redeem all keys on in origin. Now you will have anything from Steam on origin and it will run fine 🙂
I am not sure whether you having a non-steam retail version means you may only launch from origin but even so you will still be able to play all DLC from steam when launching from Origin 🙂
I can currently launch from Steam or Origin with all DLC.
