Hey John
Sounds to me like your problem is related to the hardware not communicating with each other. When doing repairs you should always disconnect the battery and then drain the remaining charge by holding the power button for 8-10 seconds. After you do this you can change your parts without the Logic Board storing previous hardware information.
The Logic Board needs to reset on hardware changes, especially the new iPhone models since they have new chips and circuits. Your problem may be as simple as the Logic Board not recognizing your replaced parts correctly.