Hi,
Thanks for detailed explanations.
1. Are you sure you are using latest version of a plugin? (2.0.1)
2. Are you sure old files from previous versions are still inside your project (thus being exported to xcode project)?
Those files should not be there:
InAppBrowserViewController.h
InAppBrowserViewController.mm
iOSInAppBrowser.mm
OrientationNavigationViewController.h
OrientationNavigationViewController.m
3. Are you able to reproduce it in empty project with imported plugin?