The instructions given in the Distribution page on the iOS Provisioning portal clearly still describe the process of creating, and including the Entitlements.plist file in a bui
I don't have answers to all your questions, but I needed to add an Entitlements.plist when I recently used ad hoc distribution for some testing. I think the documentation still talks about the 'get-task-allow' setting in the .plist, but when I followed the instructions exactly I had problems signing the app. Instead, I created an Entitlements.plist using Xcode's template. It has two or three settings, none of which are get-task-allow. I left it exactly as it was when created, and the build succeeded.
My experience in the past has been that apps submitted to the app store with an Entitlements.plist included failed the verification step.