Works fine for me with MBP, iMac, iPad all able to send and see message sent via the iPhone. Make sure iMessage and Facetime are set to the same email address and the iPhone's phone number. If necessary log everything out, log the phone in first, then the other devices. As you log each one in it should become available to be selected on the iPhone, then give you a code to enter on the device and you should be good to go.