Got the same error on UE4.19 and V1.11. Just sent the new output log on the email.
UPDATE: I deleted everything from iPhone and unreal, restarted the project from scratch. The very 1st time it run, the app gets stuck at “Loading…” screen. After rerunning the app, I get the white screen with the (Webcam init error). Tried both Launching the app and packaging it.