I am having similar problems on iOS11. The phonegap app works fine on Android (including a working splash screen), but on iOS11, loading a simple .json file into a listgroup now fails (empty listgroups) on iOS11. This has been working fine on pre-iOS11 devices. Works perfectly on Android, Volt and Desktop.
Not sure in my case if it is matter of a new 'Content Security Policy' requirement on iOS11 or not. The path to the json is simply xmlhttp.open("GET","js/myfile.json",true), relative to the index.html file, also in the manifest, etc.. Nothing has changed there. Not sure how to fix this for iOS11.
Also, trying to deploy to a registered test device via iTunes, now getting the dark icon and 'Could not install' error as well.