In a general sense, each player would have their own controller, someone with the remote and other with paired MFi compatible bluetooth controllers. Using our controller API’s you can get a count of attached controllers. I’ve heard rumors that Apples “Remote” app for iPhones can be used too, but they would probably show up as a controller as well, I just don’t know if it replaces the remote or if it comes in as additional controllers.
If you want an app running on a device that’s playing the game and want it to be talking to the Apple TV as a client in a multi-player setup (i.e. it’s not controlling the Apple TV), then search the forums for “AutoLan”. I believe @roaminggamer got it working with Apple’s latest IPv6 requirements. With it, one version of the app starts up in “Server” mode and other players connect as clients.
Rob