Airplay works fine both into moOde and Rune... And quite stable and well sounding too. If simplicity is the main task, thats the way to go.
Quite a few DACs will work too, but as Apple has issued some current draw restrictions in the later iOS it will be difficult ot say anything definently.
My iPhone 6 will play nice (with the camera connection kit) with my HRT Headstreamer Mobile but not my XMOS-based Gustard U-12 DDC. Havent tried with the S.M.S.L M8 though.