Is P2P torrent type of sharing the load possible under AppStore guidelines (be they iOS or Android)? I've honestly never even thought about this being a thing, but with large shared data that doesn't change, why not?
P2P, as in hosted from other people's phones? I think the issue is that people generally wouldn't be happy with P2P data uploads from their phones (compared to P2P on desktop, where internet is cheaper/faster, and battery isn't an issue).