RESOLVED! Remove metal plate, disconnect battery flex cable as well as the other flex cable next to it. Then connect both cables back and put metal plate back on. This fixed the "No Signal Error" and rear camera error (rear camera stopped working). This may even fix the Touch ID error after replacing LCD screen and or Touch ID home button, but not 100% sure since i haven't tested it yet.

RESOLVED! Remove metal plate, disconnect battery flex cable as well as the other flex cable next to it. Then connect both cables back and put metal plate back on. This fixed the "No Signal Error" and rear camera error (rear camera stopped working). This may even fix the Touch ID error after replacing LCD screen and or Touch ID home button, but not 100% sure since i haven't tested it yet.