Late reply, but we ended up writing our own Multipeer service using the Network framework. P.S. It was a pleasure meeting you at WWDC — now I have an image of you in my mind for all the helpful answers here!

alright.. I'll start watching some WWDC videos

Thanks for the hint, Eskimo. What a bummer that Nearby Interaction with Multipeer Connectivity is not really usable. Even Apple sample codes are useless then. Network framework is also compatible with Nearby Interaction and background ?

Yes. using Multipeer Connectivity